High school/Academy where small and shrimpy Steve, who is stereotyped as a nerd, even though he wears large jackets and loose jeans and spikes his hair. He's always seen with large stacks of books and is always in class on time and attentive because dammit all he wants to get the education and head off to college so leave him the fuck alone for trying to get the good grades.
Then there's popular everyone-wants-him Tony, who wears framed glasses has his hair all slicked back and professional and is sometimes seen wearing a devilishly-tight expensive-looking suit and is the definition of a mathematical nerd with a side of bashful, but everyone fans themselves when he crosses their path. Doesn’t help he hangs out with school president Pepper and captain of the football team Rhodey (who have known him long before the ‘popular kids’ title got stuck on them and love him for who he is).
Nerdy Steve, who will actually fight you if you call him names and gained a title for doing said thing, isn’t afraid one bit to get what he wants. So when he decides he wants Tony by george he’s going to get Tony, popularity be damned. He marches right up to him, pushes many of Tony's fanning fans out of the way, asks for a moment of his time and straight out just says “I like you, Tony. Date me.” The record screeches to a halt as Tony is left sputtering and blushing and pushing his glasses up far too quickly, leaving them crooked as he tries to find something to say. Words don’t come out of his mouth and he’s so flustered he eventually gives up and says “okay,” a little confused and still very much stuttering.
They have a wonderful first date and stay together for the whole year. Talk of the school they are and girls and boys are left devastated, hoping the two would break up. Then Steve gets sent away for summer camp. He keeps in contact with Tony via phone calls and letters all through the summer, and on the first day back Tony is standing near their favorite spot in the school waiting for Steve. He’s left with his mouth wide open as he sees Steve for the first time all buff and tall and smirking down at him and Tony shrieks as he flees all flustered because what the fuck happened to his boyfriend?? And Steve grins as he chases after him.
After Steve comes back all buff and tall and hotter, he gains a mob of fans of his own. He's no longer considered a nerd and now it's actually Tony that gains that nerd title himself by standing next to Steve and the other students start comparing Tony to the new standard Steve had set up. Girls and boys are fainting at the sight of Steve, and Tony gains the fear of losing Steve. This tall and buff man can now move on to bigger and better pastures than him. He has a whole group to choose from after all, and the group is completely willing, too.
First-year Tony carries these fears on himself but is able to push them back each day when Steve goes directly to him and never spares any of the fans a glance. He sighs in relief when Steve continues to walk with him to classes just like the year before. He relaxes his tense shoulders when Steve rebuffs a girl getting just a little too close and revealing a little too much in front of them, or a guy trying to not-so-subtly hint on his size to get Steve interested but Steve completely misunderstands. He stares at the guy very unimpressed before saying straight up “my dick is bigger, go away.” Steve never even realized the guy was hitting on him and instead thought this guy was trying to hit on Tony and was ready to defend his territory.
Second-year and they’re still together and the fangirls and boys are getting frustrated and making twice the effort, but ultimately are pushed to the side as Steve marches like a man with purpose right to Tony, who had grown an inch or two since their last year and may have filled out a little, all thanks to Steve constantly making him eat. Mostly they get their hands on take-out because Steve is shit at cooking and Tony forgets to eat so cooking is never on his mind. Tony has gained confidence here and even dares to mark his territory when fanboys and girls come sniffing. He presses himself against Steve and wraps an arm around his tiny waist. Purrs some words in his ear when one of the girls or boys try to make conversation with him. In doing this Tony always ends up pressed against a secluded wall because he might have pushed Steve a little with the purring next to his ear. He still gets all flustered as Steve turns the tables and whispers not-so-innocent things in his ear.
Third-year is when Tony comes ready to take names and heads and psychologically scar those foolish enough to earn his wrath. Third-year together with Steve brings out sassy Tony who won’t back down or hold back. He is ruthless, brash, has no chill and will probably never get a chill when Steve is involved.
Steve loves this side of him so much. His boyfriend being all territorial of him is so endearing and shows how much Tony loves him and Steve could sit and watch Tony get aggressive all day. Later on, when Steve has Tony all to himself he’ll repeat the same words Tony had said in whispers and through grunts. Tony gets embarrassed at hearing his own words thrown back at him, but dammit he couldn’t help it that girl was touching Steve's arm!
In the background, Pepper and Rhodey have to carry the person Tony had burned in his territorial fit to the nurse's office, doing damage control. Bucky and Nat for their part wipe away the evidence of tears.