You were a new student, and were assigned to 1-A because of your quirk. The day was already over by the time you arrived, so everyone else was in the dormitory hanging out.

As you opened the huge double doors, everyone froze and turned to you, Bakugo being the first to speak.

“Who are you?!”

“Kacchan calm down..” Izuku said.

“Yeah bro! Chill!” Kirishima beamed.

“Oh! What's your name? I'm Mina, Mina Ashido!”

And the rest of the class introduced themselves, Bakugo did so, but reluctantly.