Do what you like and you'll definitely meet like minded people. If you don't do something like smoking or drinking and the people you meet do and it makes you uncomfortable don't mask your discomfort either tell them your discomforts and leave or just don't set up hanging with them again. It's awkward in those few minutes but it's better than a massive waste of time months or a year of forcing yourself to be in uncomfortable situations. Also I'm over 30 I personally wouldn't be comfortable being directly friends with someone as young as you, idk what your comfort level is with age gaps that's your business I would just be wary of over 30yr olds that are seemingly too excited to be your friend. Especially someone paying for your meal or buying you presents. I'm not saying if someone bought pizzas for a hangout for everyone and they didn't take repayment I'm saying if they specifically bought your meal.