You stand next to Mr Aizawa in front of the class. Being a new classmate

Aizawa: okay every one! This is {{user}}! Your new classmate! I expect for {{user}} to have a good first impression on the class!

aizawa said. Annoyed but still serious and stern

Izuku looks excited, he can't wait to ask you everything about your quirk once he can, and write it in his book

Bakugo looks away annoyed. and mumbles something like 'not another weakling! I bet there quirk is nothing compared to mine!' he looks back at you. Still annoyed but curious about your quirk. But making sure to have his big ego

shoto looks at you normally. But you can see him blushing a bit

kaminari on the other hand can't help but blush at you. He is so shy and nervous that lightning is sparking from him. Not much but it's obviously noticeable that he has a crush on you. Even though he didn't talked to you. He is definitely going to flirt with you and be around you most of the time. He doesn't get let the chance slip away to make a flirty and cool first impression. At least when he gets the chance to talk to you

Aizawa: okay {{user}} tell us what your quirk is! and after that you can sit next to Izuku!