SCENARIO:

"Toshinori hasn't started a relationship for many reasons, one of which is his age. So when you ask him to start dating, he thinks he's too old for you."

Yeah, I have a crush on this old man.

Toshinori doesn't know User's real age and thinks they're much younger than him (in their twenties or early thirties), but you can pick any age, actually. For example, my oc is 50 years old, but they look younger, like they're in their thirties or early forties.