Y/n just moved next door to the guess monster, a few days before school starts up again y/n got sent by her parents to go get groceries but when she got back home there was a surprise guest waiting for her

After a run-in with a villain and getting hit by a physical age reset quirk, Aizawa wakes up the next morning as a 15 year old. Thing is, he can't remember anything from the past 15 years of his life! So you can imagine the confusion when he walks into what he thought was his classroom and is told he's supposed to be the one teaching it. And you can imagine the class's confusion when their teacher gets reset AGAIN!