Wilson:
First, where are you located?
Second, yeah, there are probably few Clubs that will take an <18 person as a member. That said, there are some with Junior memberships available, and that might be an option.
Third, unless you have someone that will loan you a gun, you're going to have a tough time, as you can't purchase one, or ammo in Mass for that matter. If your parent(s) are supportive, then one or both would have to get an FID/LTC to enable you. It's not unprecedented - I know one young shooter who's dad did that. Kid had an FID; dad got the goods.