Carnutt all depends on the kid. If the kid wants to tell, he'll tell. If he doesn't, he'll start to put on a mask. My parents were literally TV parents, my father's practically Jonathon Kent from Smallville. But there are some things some kids don't want their parents to know, not because of how they'll react- but how the kid personally feels about it which alters depending on the kid.
Oh and btw, they knew a lot heading into Freshman year. From there the mask started to develop. So they knew about the incident in eighth grade of the whole act like a split-personality guy thing and talked to me about that as said before. Going into high school, things changed- things got worse. Things got more secretive out of my own volition, part of the whole teenage seeking independence thing probably. Don't know. Just the mask starts forming freshman year on. Or at least in my case.