If you've never wrestled before, you're going to have a hard time "assisting" at a High School or college program. I say assisting because, most guys who hang out at an occasional practice are there to assist in some way shape or form (conditioning, takedowns, etc...). Most programs won't have the patients for you. Your best bet is to find a freestyle club. The freestyle season starts after the HS season and it's open to all ages. I coached freestyle for a year up in NorCal and we had 5 year olds, 45 year olds and everything in between. The tournys are open to all ages too. I don't know where you live, but I'd ask around and search the internet for a freestyle club near you. If that isn't an option in your area and you don't know any wrestlers that will train you, then I'm all out of ideas.
BTW, freestyle rules are similar to folkstyle, but the scoring makes for a faster match. good luck