|“||Are we ever going to see Phineas and Ferb as teenagers?
Yes. Yes, we are.
— Jeff “Swampy” Marsh and Dan Povenmire
In this special episode set ten years in the future, a teenaged Phineas must decide between two colleges while grappling with the discovery that Isabella has had a crush on him since they were kids. Ferb and the gang try to bring the two together so they can admit their true feelings for each other before Isabella leaves for school. Meanwhile, Doof wants a midlife crisis and builds a Mid-Life Crisis-Inator.
In a live-action intro, Dan Povenmire and Jeff "Swampy" Marsh, the creators of the show, read some fan letters. One of the letters asks if they will see Phineas and Ferb as teenagers, and Dan replies they will and introduce the episode taking place ten years in the future.
As summer reaches its end, a teenaged Phineas is contemplating to Ferb which college or university he should go to, being the only one in their friend group who hasn't decided where he's going yet. Ferb suggests that Phineas get in the randomizer booth they'd installed in their room and let fate decide. Phineas gets into the booth, which is full of the many acceptance letters he had received from different schools around the world. However, he is not really sure about any of the choices he is given. Baljeet comes into the room and mentions that he had just been telling Buford about what life is like in college. He tells them that he has already graduated and is now a professor, and is hoping for Buford to attend his classes; though Buford is leaning towards attending film school instead. Buford suggests to Phineas that maybe he would be happy going to the same school as Ferb will be attending in Britain, while Baljeet suggests him to going to law school like Candace, but Phineas turns these suggestions down. He finally narrows down his choices between two colleges, Danville University and Tri-State State College.
At O.W.C.A., Irving, now working as an intern, notices Doofenshmirtz's inator alert going off and informs his superior, Commander Carl. Carl was surprised by this, since Doofenshmirtz had given up evil years ago, ever since he started teaching high school science. Carl decides to tell Major Monogram about the alert. Monogram, who has since retired to Bora Bora, reminisces upon hearing that Doofenshmirtz may have returned to evil, and tells his former intern to say hi to Doofenshmirtz for him. Carl then calls Perry, who is also enjoying his own retirement. After hearing that Doofenshnirtz might be active again, Agent P gets back to work.
In the kitchen, Phineas, Ferb, Buford and Baljeet are all making snacks for themselves. Still on the topic of colleges and universities, Baljeet tells Phineas that Isabella will be attending Tri-State State, and Phineas mentions that he had not seen Isabella all that often over the past summer. Baljeet mentions that he had always believed Phineas and Isabella would have ended up as a couple by now, but Phineas says he feels as though he is stuck in the friend zone with her. Both Baljeet and Buford were amused by this thought, since they both knew about Isabella's crush and even Ferb, though Phineas himself had no idea, in which finally both Baljeet and Buford reveals it. Surprised by the revelation that Isabella had always had a crush on him over the years, Phineas decides to clear his head by going for a walk. Buford and Baljeet then decide to try to get Phineas and Isabella together before she leaves.
Meanwhile, at the building formerly known as Doofenshmirtz Evil Incorporated (the word "evil" has since been removed from the sign), Perry arrives to visit his old grey-haired nemesis. Doof gets confused to see Perry today, since it is not bowling day, but then realizes that he must have set off the inator alert. Perry gestures toward a menacing-looking machine behind him, and Doofenshmirtz assures Perry his latest inator is not evil, and that the menacing-looking machine behind them isn't even the inator. The real inator is a gold chain he had worked on, which, when activated, will help him go through a Mid-Life Crisis so he can fit in with other people his age, which he explains through song. After the inator got changed up, Doofenshmirtz's mid-life crisis begins.
At the Nosh Olé Mexican-Jewish Café, the now teenage Fireside Girls discuss the art of manipulation when Ginger attempts to persuade Baljeet, whom she already have a relationship with, to go to the movie she wants to see, rather than the one he wants to see. Isabella, who is working as a waitress there for her mom, brings the girls their order. Gretchen asks where Baljeet is, and Ginger replies he is at Phineas' house. The girls also contemplate how Phineas and Isabella are not a couple. Deciding that they should take it upon themselves to set Phineas and Isabella up with each other before she leaves for college, Adyson instructs Ginger to text Baljeet about their plan. In the living room, Baljeet receives Ginger's text, but does some manipulation of his own to make it seem like it was Ginger's idea all along.
Doofenshmirtz, who has now dyed his grey hair black and is riding a jet-ski with Perry, crashes his jet-ski into a sailing yacht. Excited in the heat of the moment, he then suggests taking the yacht for a spin, but the yacht sinks and Doofenshmirtz's hair dye begins to wash off in the water, making it grey again. Doofenshmirtz then decides to get a sports-car and swims his way back to shore.
At the Danville Retirement Home, Phineas meets up with Nana Shapiro. Phineas tells Nana he is still indecisive about where to go to college. Nana then mentions that Isabella came over to say goodbye, which surprises Phineas since Isabella's college does not start for another two weeks. Nana tells him she is actually leaving today as soon as her waitress shift ends at the Café. Nana Shapiro suggests he go to the restaurant if he has anything to say to her.
In the backyard, the teen Fireside Girls, Baljeet, and Buford begin setting up a romantic dinner for Phineas and Isabella, in which Ginger reminds her that this is just like their childhood years. Ferb suggests to leave well alone and not force them to get together, but Adyson suggests otherwise. Gretchen explains further the romantic dinner and Katie ask if it doesn't work that Buford brings the sign to show them "Think About Love".
At a car shop, Doofenshmirtz is looking at sports cars to try. He tries a red one, but he crashes it. The salesman tells him they have the same model in yellow. This excites Doofenshmirtz. In the kitchen, Ferb and the girls are all cooking the dinner. Baljeet suggests to Buford that he wear the cupid costume, since it worked for him and Mishti, but Buford refuses. Upon hearing about Mishti, Ginger begins to get jealous, but Adyson tells her to let it go. In downtown Danville, Doofenshmirtz is taking his new sports car and Perry for a wild ride. During this, they latch to a dumpster. Doofenhsmirtz lets it go at the next turn and the dumpster speeds past the restaurant.
Isabella begins to say goodbye to her mother as she gets ready to go to college. Her mom gives Isabella her last paycheck and a hug. As Isabella walks away and begins to put her paycheck in her wallet, a photo of Phineas drops out. She picks up the photo then begins to reminisce about all the past summers she spent with Phineas and contemplates What Might Have Been. Phineas reaches the restaurant, but Vivian tells him he just missed her. She then tells him she knew about Isabella's crush as well. Phineas leaves and does some contemplating of his own in the song about how oblivious he was to Isabella, even though, in hindsight, her attempts at romantic advances were really obvious.
Back in the backyard, Ferb puts a vase of flowers on the table and the girls believe the dinner is perfect. They attempt to call Isabella on their cells, but various things hinder them from doing so. They are so distracted that they fail to notice the dumpster from earlier rolling into the backyard and taking the romantic dinner away. Katie notes this reminds her that this is just exactly the same like when they were kids.
By this point, Doofennshmirtz and Perry are in a plane about to skydive. Doofenshmirtz decides to hit on the jump instructor, but she pushes him out of the plane. Perry acknowledges her politely and quickly jumps out before she can push him too. As they fall, Perry opens both his and Doofenshmirtz's parachutes. Doofenshmirtz decides he has had enough of his mid-life crisis and takes the inator off and drops it. Below, the inator latches to Lawrence, who, under the effects of the inator, rushes into the kitchen and tells Linda that he is impulsively going to switch his morning tea from Earl Grey to Darjeeling.
Phineas reaches Isabella's old house, but then notices her sitting on one of the steps of his house across the street. He walks over and sits next to her. Isabella tells him she came to say goodbye since she's heading to college early, because she was accepted into various extracurricular activities at the school. Phineas then tells her what Baljeet said to him about her having a crush on him, which Isabella admits to. She then says she gave up on the idea of getting together with him around high school, and Phineas admits that was when he began to have feelings for her. The two sadly contemplate the bad timing of their respective crushes on each other. Isabella then mentions that she is going to Tri-State State, which makes Phineas' decision about which college to go to easier: he decides to attend her college so they can attend the same place. The Fireside Girls and Baljeet, Buford and Ferb, who had come around the house from the backyard while Phineas and Isabella were talking, overheard their conversation and are happy to see that they are together now. As the girls give farewell to Isabella, Phineas and Isabella embrace, and Isabella gets back in her car, telling him that she'll see him in two weeks, and drives away. Ferb approaches Phineas and commends him for his choice. Vanessa then drives up in the yellow sports car and Ferb gets into the passenger's seat. They offer Phineas a ride, to which he accepts.
While driving, Isabella comes to a stoplight, and Vanessa's car pulls up next to hers. Phineas gets out of the backseat, and Isabella gets out of her car to ask Phineas what he is doing. Phineas replies, "This," and then kisses her. Off to the side, watching from their car, Vanessa jokingly tells Ferb that she never realized Isabella had a thing for Phineas, to which he replies, "Seriously?". She then tells him that she was just messing with him, and that everyone knows, before the light changes to green and they drive off. As Phineas and Isabella kiss, Isabella tells Phineas that it was worth the wait, to which he agrees.
Swampy begins to sob uncontrollably when seeing the gang all grown up and going to college. Dan tries to console him, but excuses himself and leaves the still weepy Swampy alone.
Read the transcript of Act Your Age.
- "Mid-Life Crisis"
- "Ballad of Badbeard" (instrumental)
- "What Might Have Been"
- "Danville for Niceness" (instrumental)
Third verse of "What Might Have Been" while Swampy continues to sob in the background. During the logos, Dan yells at him to get a grip.
|View the image gallery for "Act Your Age".|
I know what we're gonna do today
The "Too Young" Line
Swampy: Are we ever gonna see Phineas and Ferb as teenagers?
Dan: Yes. Yes, we are.
Isabella: Well, I guess I'll see you in two weeks.
Phineas: Yes. Yes, you will.
Isabella: That was worth the wait.
Phineas: Yes. Yes it was.
Phineas: Ugh! I'm running out of time, Ferb. I gotta choose a school. Do I stay local or go abroad? Trade school? Art school? Come on, Ferb. Help me make a decision.
Ferb: Get in the booth.
Phineas: Okay, Kjobstaad Academy. Uh, which one was that again?
Ferb: Mmm...great physics department, Norway.
Phineas: Yeah. He's going to Camford on Oxbury. Heh heh! "Camford on Oxbury". It sounds like a wizard school.
Ferb: It's not a wizard school. Well, there is some wizarding.
Adyson: And when we get them to come back here and see it and each other, they're bound to fall madly in love like they were always meant to be!
Ferb: You know, you can't force these things.
Ferb: So Tri-State State, huh? Good choice.
Phineas: Hi, Nessa! Where're you guys goin'?
Vanessa: Oh, Ferb's takin' me out for Ukranian food.Ferb: Can we drop you anywhere?
Vanessa: I never knew she had a thing for him.
Phineas: So she's...leaving?
Baljeet: Yes. Huh. I always thought the two of you would end up together.
Phineas: What'cha doin'? Heh heh.
(Isabella looks up and smiles.)
Isabella: Phineas, what are you doing?
Phineas: This. (Phineas kisses Isabella)
Hey, where's Perry?
Perry's entrance to his lair
Perry is sleeping and receives a call from Commander Carl
Oh, there you are, Perry
Doofenshmirtz .... Incorporated! ("Evil" word was already scrapped from the sign)
Phineas: Yeah, things seemed a lot easier when we were young and waiting for our voices to drop.
Baljeet: [deep voice with American accent] Hey, guys. (coughs, normal voice) Oh! Something was caught in my throat.
Baljeet: I was just giving Buford some pointers on collegiate life. Since I've already graduated and have been accepted as a professor, I could pull some strings and get him into my school. Just think, Buford. You could be my student! I could be the boss of you!
Buford: Don't get too excited. I'm goin' to film school. I'm concentratin' on tragedies. The story of a struggling orphan's transcendental search for meaning in a post-apocalyptic society.
Candace: And that concludes my dissertation on modern investigative techniques for establishing proof of guilt with or without physical evidence.
(The judges all give her a standing ovation.)
Buford: Hey, the epic struggle of a triangle-headed boy: to choose between two schools.
Baljeet: Pretentious alert.
Irving: (on the phone) Sir, it's the old Evil Scientist Alert System! It's showing inator activity on a Doctor Dooferdsmits.
(Split screen to reveal Carl, now much older and wearing a uniform and mustache much like Major Monogram did.)
Buford: (looking in the fridge) Why do parents buy such weird food? Everything's lite, low, non, free, or diet.
Phineas: Well, why didn't you guys ever tell me?
Baljeet: We are guys. We do not talk about feelings.
Doofenshmirtz: I wanna do something fun and exciting and...also incredibly stupid.
Holly: Ginger, are you texting Baljeet again?
Ginger: Yeah, we're at odds deciding what movie to see later. He wants to go to the one about that planet and I want to see the one with that guy.
Isabella: Do we have chopped liver? What do you think this place is? Chopped li— Oh, that doesn't really work.
Buford: Ginger texting you again?
Baljeet: Yes. The girls want to get Phineas and Isabella together.
Doofenshmirtz: Hey, this is one of those fancy sailing yachts! We could sail around the world in this thing! We could, we could visit exotic ports, fight pirates! We'd like a couple of seafaring Huck Finns and the ocean would be our home! Or maybe we could wrestle some alligators! No, wait, even better, sports car!
Nana Shapiro: Phineas, look at me. If you have anything you need to say to her, you'd better go over to the restaurant and say it. Her summer's almost over.
Phineas: I—You're right. Thanks! (he runs off)
Gretchen: When they first walk in, we'll play the songs I put on this playlist. They're all about love, and it will trigger them to start thinking about love. Then we have these streamers and balloons in both of their favorite colors, which will stimulate the romantic centers of their brains making them think about love.
Katie: What if it doesn't?
Doofenshmirtz: Sure you don't have anything else that's more ridiculous or irresponsible?
Salesman: Nope. This is as dumb as they come.
Doofenshmirtz: So, what else ya got?
Salesman: We've got another one just like it, but in yellow.
Buford: Oh, yeah, it's the perfect romantic setting out there. It will be like love kicked them both in the face.
Baljeet: Buford, the table looks great, but there is one thing that will make it perfect.
Ms. Garcia-Shapiro: Phineas, honey, how are you?
Phineas: Hi Ms. Garcia-Shapiro. Uh, is Isabella here?
Adyson: Alright, let's get 'em over here now. (takes out her cell phone) Oh, wait, I don't have any charge.
Gretchen: Oh, this is her old number.
Doofenshmirtz: (to the jump instructor) Hi there. Y-Y'know, one of the best things about being a successful scientist is that I get to meet lots of attractive women, such as yourself.
Jump Instructor: You want to know the best part about being a jump instructor?
Lawrence: Linda! I don't know what's come over me, but I'm starting to get the most wild and uninhibited ideas! You know how every day for the last 20 years I've relaxed with a nice cup of Earl Grey? Well, not today, Linda! Today, I'm putting out all the stops! Darjeeling!
Linda: You...are a madman.
Phineas: You know, Baljeet said something funny. He said you had a crush on me back in grade school.
Isabella: Oh. Yeah. I had a big crush on you.
Isabella: Phineas, what are you doing?
Jeff "Swampy" Marsh: (sobbing) I can't believe it! It seems like only yesterday we were drawing our first doodles of these kids on the place mats of that...
Dan Povenmire: (consoling Swampy) Yeah, I, I know, it's a... It's a sweet episode.
Dan Povenmire: (to Jeff "Swampy" Marsh) Oh, get a grip, Swampy.
- This episode takes place approximately 10 years after the events of the series. Given that school starts two weeks later, it takes place around mid/late August.
- Doofenshmirtz's old appearance marked the fourth time an elderly/middle-aged version of Heinz was featured in the show. The first was in "Lights, Candace, Action!" and the second and the third were in "Phineas and Ferb's Quantum Boogaloo".
- This is the first episode to premiere in 2015.
- According to this episode, Isabella had come over "every day for eleven summers." One of the montages during "What Might Have Been" suggests the summer the rest of the show was set in takes place sometime in the early-middle of that period.
- In addition, this episode shows Phineas has been (on the series' present, will be) engaging in Big Ideas every summer.
- It appears that everyone, including Vanessa Doofenshmirtz and Vivian Garcia-Shapiro, were aware of Isabella's crush on Phineas, while Phineas remained completely oblivious.
- Dan Povenmire and Jeff "Swampy" Marsh appear as themselves in live-action bookending the show by reading some fan mail.
- This episode depicts that Monty and Vanessa were no longer dating, as the latter ended up having a relationship with Ferb instead.
- Ironically, Baljeet mentions in this episode that "guys don't talk about feelings", but he wanted to talk about his feelings in "Hide and Seek".
- Dan Povenmire confirmed that Ferb's real name was Ferbs in this episode.
- Ferb once foreshadowed his name is a short of Ferbs in "Vanessassary Roughness".
- Candace's future as a law student and her dissertation presentation was probably inspired by her constant failed attempts on busting her brothers, which eventually replied by the female panelist, whom she felt like busting someone.
- It is revealed that Ginger was aware of Baljeet's crush on Mishti and was very jealous.
- The only characters who looked like they normally do are Linda, Lawrence, Vivian, Vanessa, Perry, and Nana Shapiro, though Doofenshmirtz looks like his usual self, the only difference is having grey hair.
- Of the characters above, Vanessa is the only character who does not wear her usual clothes.
- While most of the child characters have their voices lowered a bit to match their ages, Ferb and Irving's voices are the same as they were when they were younger.
- The characters' respective futures:
- Candace: Goes to law school.
- Baljeet: Becomes a professor at an unspecified college. Dates Ginger Hirano.
- Buford: Attends an unspecified college and majors in film.
- Ginger: Dates Baljeet.
- Dr. Doofenshmirtz: Gives up evil after becoming a science teacher at Vanessa's old high school, and rarely makes any new inventions. He becomes Perry's bowling buddy.
- Carl: Becomes the head of the O.W.C.A., known as Commander Carl.
- Major Monogram: Retires to Bora Bora.
- Agent P: Retires, but is still on-call for when his old nemesis becomes evil again. He and Heinz are bowling buddies.
- Irving: Works at the O.W.C.A., presumably as an unpaid intern and gets a new car.
- Phineas: Finally admits to Isabella that he's had a crush on her since the beginning of high school, and enrolls in the same school she will be attending, Tri-State State College, so he can begin a romantic relationship with her.
- Isabella: Finally admits to Phineas that she's had a crush on him since grade school, begins a romantic relationship with him, and attends Tri-State State College with him. She also worked at her mother's restaurant as a waitress during her teen years.
- Vanessa : Owns a sports car, and dates Ferb.
- Ferb: Attends Camford-on-Oxbury in England and is dating Vanessa.
- Vivian Garcia-Shapiro: Works at her family restaurant.
- In both production and airing order, this is the last regular episode.
- This is the last double-length episode where no one says "Oh, there you are, Perry."
- On November 15, 2012, Robert F. Hughes posted a tweet stating that Madison Scheckel had come to write a Phineas/Isabella song. 
- On December 14, 2012, Dan Povenmire tweeted the photo of Vincent Martella singing the aforementioned song. 
- On March 1, 2013, Dan Povenmire, Jeff "Swampy" Marsh and Jake Whetter had a Spreecast chat. Fans were welcome to send in questions using Spreecast, Facebook, or Twitter with the hashtag "#PlatypusDay". During Spreecast, Dan and Swampy had confirmed an emotional Phineas/Isabella episode in Season 4, and mentioned that the song made them both cry. 
- On May 10, 2013, Robert F. Hughes mentioned via Twitter that this episode would not be the Season 4 finale and revealed its title to be "Act Your Age".
- On May 18, 2013, Bernie Petterson has confirmed that he and Kim Roberson were the writers and storyboard artists for this episode.
- On August 28, 2013, Robert F. Hughes confirmed that this episode would be a 22-minute long episode (30 minutes with commercials).
- On December 16, 2013, Aliki Theofilopoulos Grafft confirmed that this episode's animation was already done at least for a week from that moment.
- On January 14, 2014, Dan and Swampy posted a tweet from their recording session for the episode with Alyson Stoner. 
- On January 22, 2014, Dan posted two script doodles of "Act Your Age".
- During their July 22, 2014 Spreecast to promote "Phineas and Ferb: Star Wars", Dan Povenmire noted that this episode would air in February 2015.
- A few scenes of this episode were shown at the 2014 Comic-Con International in San Diego.
- The teenage versions of Phineas and the gang were drawn by DeviantArt user Ashley Simpson, alias "KicsterAsh". Dan Povenmire created a DeviantArt account for himself just so he could ask her to design for this episode. Simpson is given a credit for "Character Design" at the end of the episode.
- Of the teenage Fireside Girls, only Gretchen and Adyson have the same voice actresses as their younger counterparts. The voice of Ginger is provided by Ming-Na Wem, who not only voiced Ginger's mother Dr. Hirano, but is also the real-life mother of Michaela Zee, the current voice of Ginger.
- Rumors circulated among the public that this episode would be the series finale. Because of this, many crew members have made public announcements to deny it.  Dan Povenmire referred to the episode as an "emotional finale" but clarified that it would not be the season finale. 
- This is, however, the last episode (next to the last) before the series finale.
- After the Russian version aired, Dan Povenmire explained on Twitter that he did not want it to air anywhere else before it aired in the United States. 
- Some of the voices, noticeably Buford's, were electronically modulated down to make them sound ten years older.
- This is the last full 22 minute episode (minus ads) of the series, as well as the last regular episode overall.
- In the Latin American Spanish dub, the title is "Adolecentes" which means "teenagers".
- The scene where Phineas kisses Isabella got put in after the animatic got finished, and storyboarded by Dan Povenmire. According to Dan at SDCC 2015, when his wife saw the storyboard of this scene, she cried.
- In Disney+, in Indonesia, the Mexican Jewish Café word below Nosh Olé is censored for unknown reasons. Some dialogues were also cut out, such as "What the heck" (by Carl), "Text Lover Boy" (by Adyson), and the zoomed-out scene of Phineas and Isabella's kiss.
- May 10, 2014 (Television New Zealand)
- August 12, 2014 (Disney Russia - YouTube)
- March 6, 2015 (Disney Channel Russia)
- March 7, 2015 (Disney XD Canada)
- March 14, 2015 (Disney XD Poland)
- March 19, 2015 (Disney XD UK and Ireland)
- March 20, 2015 (Disney Channel Scandinavia)
- April 3, 2015 (Disney Channel Asia)
- April 20, 2015 (Disney Channel Italy)
- June 8, 2015 (Spain. On the internet)
- June 13, 2015 (Disney Channel Japan)
- June 20, 2015 (Disney XD Spain and Disney Channel Latin America & Brazil)
- July 1, 2015 (Disney XD Germany)
- July 2, 2015 (TV5 Philippines)
- July 17, 2015 (Disney Channel Hungary and Czech Republic)
- August 4, 2015 (Disney Channel Israel)
- August 6, 2015 (Disney XD Australia)
- August 9, 2015 (Family Channel Canada)
- September 5, 2015 (Disney Channel Spain)
- September 6, 2015 (Disney Channel Portugal)
- April 29, 2016 (Disney Channel Poland)
- The ending credits misspell Milly's name "Millie."
- Buford said that Isabella came to Phineas and Ferb's house every day for eleven years, but she does not show up for some projects in the summer the timeline takes place in.
- In What Might Have Been:
- In Isabella's part, when her young adult, tween and preschooler selves sing backup, tween Isabella's right foot is standing on young adult Isabella's left foot.
- When we see Isabella entering the backyard in her toddler, kid, tween and teen ages, if examined closely it seems that she somewhat becomes the same size as the fence.
- When Phineas is giving Isabella a flower, the insides of the bottoms of Isabella's pant legs become superimposed over her shoes.
- Phineas has freckles on his head when seen as a toddler, kid and teen, but when seen as a preschooler and tween, he does not have them.
- When the gang are first seen in the backyard, Adyson's headband is missing.
- When the dumpster passes the Nosh Ole Café, the trash can could be seen on the left side of the door. After Isabella and Vivian exits the café, the trash can is seen on the right side. This happens again when Phineas is about to enter the café.
- When Adyson suggests Ginger to manipulate the situation, for some reason Gretchen's left eye is not attached with her face.
- When the dumpster hits the dinner setting, some decorations are still remain on the grass. After Baljeet asks the company to take a look at the ruined setting, the decorations suddenly swept away.
- When Vanessa pulls up in the yellow sports car it only has two seats. When she pulls up beside Isabella's car it has an extra third seat in the back on its own. Additionally, there are no other seats beside the one in the back.
- During Mid-Life Crisis, Perry's jetpack disappears throughout the song and then reappears again after the song ends.
- When Phineas comes up to Isabella's car at the end she rolls down the window and leaves the car. When the car is in the next shot the window is rolled up.
- When Carl calls Monogram in Bora Bora he dials only 7 numbers, but when making a call from the US to the French Polynesia you would have to dial 12 numbers (011 + 689 + local number).
- Baljeet mentions the time Isabella's eyes formed hearts, which was only seen in the very first episode, "Rollercoaster". Oddly enough, he wasn't introduced yet in the said episode.
- When Buford enters the house, Adyson is seen stirring in the kitchen and she doesn't wear an apron. When Buford approaches her as the screen zoomed in, Adyson suddenly wears her apron.
- When Katie says that it was exactly like their childhood, Adyson's clothes are all blue instead of a blue top and skirt.
- At the same time, Katie's hair moves from behind her arm in one frame to in front of it in the next.
- Also, Adyson's and Gretchen's phones changes color from black to white.
- When Baljeet said that he and his friends were try to get Phineas and Isabella together, he has two mouths at one point.
- When the gang finished setting up the dinner and starts to call Isabella, Milly is missing. Also, when the Fireside Girls give farewell to Isabella, she is nowhere to be seen.
- The Baljeet/Ginger affair comes up again, this time with them as a couple. ("Isabella and the Temple of Sap", "Happy New Year!", "Bee Story", "Druselsteinoween", "Night of the Living Pharmacists")
- Carl mentions placing Doof as a high school science teacher. ("Doof 101")
- Carl is the head of the O.W.C.A. again. ("Phineas and Ferb Save Summer")
- Baljeet mentions the time Isabella's eyes formed hearts ("Rollercoaster").
- Buford's interests to attend film school and focus on post-apocalyptic movies are foreshadowed in "Phineas and Ferb Save Summer", where he made his own movie about the world apocalypse.
- Buford wears a diaper for his cupid costume again and Baljeet mentions when Buford wore that costume during his and Mishti's date. ("That Sinking Feeling")
- A Hightail Delivery Company truck is once again seen. ("Delivery of Destiny", "Mind Share", "Night of the Living Pharmacists")
- During the song, flashbacks were seen from the following episodes:
- Ferb's crush on Vanessa made a reappearance with them going out on a date. ("I Scream, You Scream", "The Chronicles of Meap", "Vanessassary Roughness", "Summer Belongs to You!")
- In scene where Isabella asks Phineas what he is doing, he replies, "this" and proceeds to kiss her. Jeremy said the same thing to Candace right before they had their first kiss at the end of "Phineas and Ferb: Summer Belongs to You!".
- Doofenshmirtz wears the same trunks he does in "Put That Putter Away".
- Family Guy - Dan and Swampy appear reading mail as Brian and Stewie do in "Viewer Mail".
- Harry Potter - Phineas mentions that the school Ferb will be attending in England, Camford on Oxbury, sounds like a wizard school. Ferb denies this, before admitting that there is some wizarding.
- The Crystal Maze - When Phineas is in the booth surrounded by flying paper it looks like the last round of the UK game show (originally presented by cast member Richard O'Brien)
- The Diamond Head Game and Beat The Clock - The booth that Phineas and Ferb use to decide what college to go to bears a resemblance to the volcano wind machine from the 1970s Hawaiian based The Diamond Head Game and the 'Swirling Whirlwind of Cash and Prizes' from the 2002-2003 version of the classic stunt show Beat the Clock.
- Cambridge and Oxford - Ferb's college choice is a parody of these two rival English Universities.
- The Adventures of Huckleberry Finn - When Doofenshmirtz is standing on the Yacht he references to Perry the plot to the book except on the ocean and not on a river.
- The Brady Bunch - The way Ginger says "Mishti, Mishti, Mishti" is like Jan's "Marsha, Marsha, Marsha".
- Grease - When Phineas and Isabella kiss, the romantic orchestral/choral rendition of Isabella's "What'cha doin'?" theme strongly resembles the rendition to "Love is a Many Splendored Thing" from the opening scene of the 1978 film adaptation of Grease.
- The sports car that appears in this episode strongly resembles a Pagani Zonda. In the song "Midlife Crisis", the green sports car when Doofenshmirtz sings "Sports Car Buying" Resembles a 2002-2005 Honda NSX.
- This is the first episode to take place entirely in the future and the second to involve the future ("Phineas and Ferb's Quantum Boogaloo").
- Third episode where Dan and Swampy are appear on-screen (after "Tri-Stone Area" and "Phineas and Ferb : Star Wars") and one of several episodes to use some form of live action. ("Rollercoaster", "Candace Loses Her Head", "Lights, Candace, Action!", "Phineas and Ferb Musical Cliptastic Countdown Hosted by Kelly Osbourne", etc.)
- Fourth episode to heavily involve Isabella and Phineas's relationship. ("Happy Birthday, Isabella", "It's No Picnic", "Operation Crumb Cake")
- Ninth time Isabella doubts her feelings toward Phineas, although this episode, she doesn't get annoyed toward him. ("Out to Launch", "That Sinking Feeling", "The Beak", "Phineas and Ferb: Summer Belongs to You!", "Canderemy", "Happy New Year!", "Druselsteinoween", "Night of the Living Pharmacists")
- O.W.C.A.'s headquarters is seen again ("Traffic Cam Caper", "Delivery of Destiny", "Agent Doof", "La-Candace-Cabra", "Phineas and Ferb Save Summer").
- This is the second time that Ferb directly interacts with Adyson ("The Great Indoors").
- Third time that Isabella and Phineas kiss (Phineas and Ferb the Movie: Across the 2nd Dimension, "Phineas and Ferb: Star Wars")
- First time Phineas kisses Isabella, as Isabella was the one to kiss him the previous two times. However, this is the first time that the regular universe versions of Phineas and Isabella have ever kissed that they are aware of. (Their memories were erased in Phineas and Ferb the Movie: Across the 2nd Dimension and the other was non-canon, being alternate versions of their characters in the "Star Wars" universe.)
- This is one of several episodes in which Perry doesn't battle Doofenshmirtz, due to the latter having given up on evil.
- Perry does not interact with any of the kids in this episode, only with Doofenshmirtz, Carl and one other minor adult character, and he is not shown in his "doesn't-do-much" persona. None of the kids comment on his absence, as no one says "Where's Perry?".
- Ninth episode where Doofenshmirtz's inator is not evil ("Tip of the Day", "The Chronicles of Meap", "Thaddeus and Thor", "Candace Disconnected", "A Real Boy", "Troy Story", "Father's Day").
- Second time Perry is seen terrified with Doofenshmirtz's driving. The first was during Drusselstein Driving Test Waltz ("The Doonkelberry Imperative").
- If Perry was adopted five years before the series and this episode is ten years later in the future, then he is at least fifteen years old here, but he doesn't seem to be old at all in this episode. In "Phineas and Ferb's Quantum Boogaloo", 20-years-later Perry does look old and wrinkled.
- In the real world, platypuses in captivity may only live up to the age 17.
- Candace only has a brief cameo in this episode again. ("Isabella and the Temple of Sap", "Brain Drain", "Buford Confidential")
- This is also the first and only two-part episode where Candace has just a cameo.
- Carl says, "Great googly moogly!", which was previously Monogram's catchphrase.
- This marks the second time someone suggests giving Perry a girlfriend. ("Nerds of a Feather")
- Final episode to heavily involve the Fireside Girls, the fifth time every Fireside Girl has a speaking role ("Isabella and the Temple of Sap", "Bee Story", "Happy Birthday, Isabella", "Night of the Living Pharmacists"), and the last time any of them have speaking roles.
- Fourth time Carl is seen with a mustache. ("Atlantis", "That's the Spirit", "Phineas and Ferb Save Summer")
This episode received positive reviews from critics and fans. John Blabber of bubbleblabber.com gave this episode an 8/10. 
- Vincent Martella as Phineas
- Ashley Tisdale as Candace
- Thomas Sangster as Ferb
- Caroline Rhea as Mom
- Richard O'Brien as Dad
- Dan Povenmire as Dr. Doofenshmirtz, Himself, Additional Voices
- Jeff "Swampy" Marsh as Major Monogram, Himself, Male judge
- Tyler Mann as Commander Carl
- Maulik Pancholy as Baljeet
- Bobby Gaylor as Buford
- Alyson Stoner as Isabella
- Olivia Olson as Vanessa
- Jack McBrayer as Irving
- Eileen Galindo as Mrs. Garcia-Shapiro
- Carol Kane as Nana Shapiro
- Ariel Winter as Teen Gretchen
- Madison Pettis as Teen Adyson
- Dana Davis as Teen Holly
- Ming-Na Wen as Teen Ginger Hirano
- Dannah Phirman as Teen Milly (misspelled and credited as "Millie")
- Soleil McGhee as Teen Katie
- Mackenzie Phillips as Female judge, jump instructor
- Diedrich Bader as car salesman
- Super brilliant
- First look: Future is now for 'Phineas and Ferb'
- Laying down the Phineas and Isabella song
- Absolutely killing in the studio on a Phineas/Isabella duet
- Live with Dan and Swampy!
- Lots more shows coming so get ready
- Tentative name of episode
- It will not disappoint
- And getting a bit verklempt.
- Watching a bit of Act Your Age
- Doodle one
- Doodle two
- Phineas and Ferb Act Your Age Featurette
- Why does everyone label “Special to them” as “LAST EPISODE TO AIR GUYS OMG”
- Lots more shows coming so get ready
- We did NOT want AYA airing anywhere
- Review: Phineas and Ferb "Act Your Age"
"Last Day of Summer"