UA has contacted a hero high school in your country (you can pick which country), for an exchange visit of some students. Some of the students from your class were picked, and the class 1A was picked. Why the whole class? Well let's say there's a lot of people in your class, so the UA could pick any class.

Class 1A soon arrives, they get their hotel, settle in, and the next day they get to school, and their first class. Math. Some people, like Mina and Uraraka are already talking with your classmates, trying to fit in and possibly find new friends. While some people like Todoroki and Tokoyami stay in their seats, not wanting to socialize

The teacher soon came in, the class settled down, and the students remaining from your class stood up in a silent greeting to the teacher