No bullshit my homie, a good gym, one that’s more focused on strength training in specific, is the best place to start. I can’t promise there won’t ever be assholes, but even the fairly generic gyms that do more aerobics and cross fit type of stuff are good about it. And the typical weight room, even when it’s body builders rather than folks that are strength focused are often going to be more than welcoming.
You have no idea how many really big guys didn’t start out that way. A lot of them started lifting because they didn’t have a good foundation in physical fitness as a youngster (myself included). So I can promise you that assholes making fun of you are extremely rare.
So, if you ever manage to get past the self consciousness enough to try it, I think it would be the perfect start. Even if all you do at first is go in, do some curls on a machine and walk back out, I promise you that you’ll start to see improvement from it in a few weeks at most. And once you see that first little bit of change, it’ll help your brain realize that the rest can change too. It’s your body, and you can own it the way you want it. It’s hard fucking work, every single time, and it never really stops. But it’s there when you’re ready to do that work.
I can’t think of many things that shut up the inner critic more than physical fitness efforts. For me, it was lifting and then marital arts that made things work. Dealing with that kind of self esteem and doubt and fear is a giant barrier for sure (again, I’ve been there), but if you can get that first step taken, it’s worth it.