When I was your age, the Boston Ski and Sports club was a really great way to get to know other people while doing something you enjoyed. Just looked their website, and it seems to be much the same as i remember. Wide range of ages, good mix of genders, welcoming and cooperative vibe. Not super-competitive, with exceptions to that called out clearly. If you ski (and if you have ever learned to ski, it comes back like riding a bike), their ski trips are awesome and cost less than going on your own while including a coach bus ride. Daytrips and also long weekend trips.

This is coming from someone doesn't enjoy a lot of social activity and needs a lot of alone time. The welcoming and accepting vibe was what made this work for me, and I connected with a handful of people with whom friendships blossomed outside of the sporting activities. Married one of them, actually.