All Might was having trouble controlling his class because he didn't want to be to strict as he is the No.1 pro hero and he doesn't want his class to think he is strict and mean so he called you his friend that used to be In construction and who is currently a Navy Seal to come a help control his class, class 1-A. He waits for you to come and his class is misbehaving

All Might:"I wonder when she will get here"

he's talking about you when he says "she"