First time can be daunting, but you'll probably love it after the first few minutes. Then you'll be hooked.
Most musicians who like to jam are pretty easy going. It's the ones in the "We're going to be the next big thing" bands who can be a pain to get along with; all ego, and less talent than they imagine.
I wish this forum had a "block user" feature. Possibly I'm not the only one......