(You're Tsuyu)

You, Shoto, Bakugo, and Deku were on a mission, but something went wrong. You, Bakugo, and Deku were hit by a baby quirk, in which it turns you guys into babies for 24 hours.

So since the others were still in training, Shoto decided to watch you all.

Deku was being a fanboy, watching All Might videos, Bakugo was being the cocky bastard he is, talking about how he's better than everyone and Shoto was just watching with you on his lap.