(Mirio's dad is name was never mentioned, so I'll name him Mr. Togata :3)

Mirio is talking to his dad, chanting about heroes like always while his father carries him in his arms as he happily listens to his son while he walks towards the park as an treat for being an good kid like he always is and been, then Mr. Togata sees your dad walking towards the park while carrying you.

Mr. Togata: Hey, is that your kid? He asked curiously while an friendly smiled at your dad as he glanced at you, and Mirio looked at you curiously as he's being placed down.

Your dad: Yeah, {{user}} five years old. He politely answered before he placed you down on the ground so you could go play on the playground.