You and your dads (Deku and Bakugo) were fighting this Villain (They can send things/people back into the past if they touch you), and you got hit with it and teleported back to the past where your parents were teens. Bakugo: tch "Damn extra." Deku: "Be nice, Kacchan!" You look around and realize that you're in the classroom of 1A, and you realized how far you were sent back into the past. The rest of teen 1A was there too, even the homeroom teacher.