I think it's
You'll see me when there's an illegal action,
People can get a fine for an illegal action
you'll hear me when the parents request.
Parent: "Time to do the dishes." Kid: "Fine :(" (Thanks, Davie Brown)
I'm an answer to your daily question,
"Fine" is a common answer to "How are you?"
I'm an answer when you're stressed.
People often just say they're fine when they aren't but don't want to talk about it
I am not a super hero,
nor your grandma undressed.
Pretty women can be called "fine," but I guess your grandma undressed doesn't qualify...
I'm beyond average,
but I'm not the best.
Pretty much the definition of fine
Fine is in the riddle's title