mmmh AUs high school FrostIron AU??
Okay high school is so not my jam but let's do this!
Everyone assumes Tony is good at everything and everything comes easy to him but it's not. The problem is that he is great at His Shit but he will pick His Shit he likes over studying for actual exams or tests, let alone read a book he didn't pick himself cause it's needed for class.
Loki, on the other hand, is actually good at everything. He's an arts nerd, he's a master at humanities, he's good enough at sciences, and he grew up with a family with enough pressure he knows how to force himself through boring shit.
They both HATE physical activity though. But they're also tricksters at heart and both got themselves (not really fake) doctor's notes that allow them to just not take part in PE.
As a result they spend every PE class together in the small but cozy library in the school's basement.
At first they pick different sofas and read quietly and don't interact. But then one day Loki is reading Stephen Hawking and Tony absolutely freaks out at seeing he's a nerd too and draws him into a discussion.
Loki makes Tony read Shakespeare.
And they hit it off and get on like a house on fire.
But for prom they're both too scared to ask each other.
So Thor and Pepper do it for them. They both blush and eventually accept and wear matching suits with red and green ties.