Learning to connect with others in my age group (24)

Making friends or attempting to connect with anyone has always been an issue for me, but especially finding people within my age range.
I’m deeply high masking, and I’ve found a spot where in part of me just trying to work and improve on myself lately, I’m also trying to have a better attitude in combination with the way I speak and present myself.
This is of course deeply exhausting, but I guess it’s paying off? Either way, I want to go out more and try to meet people, but I still find social situations greatly intimidating and hard to navigate.
I have a history of being avoidant and closed off because I’m afraid of rejection, judgement, and mockery from even trying, since it has happened so many times before.
I struggle a lot with hearing people in places like book stores or other places where they’re talking about things that I have the same interest in, but being too afraid to join in as to not be a bother and avoid another upsetting rejection.
My self-image and confidence are terrible too, so I’ve just been used to this conditioning that I’m disgusting, ugly, broken, and unlovable. That I will never find my community or place of belonging and be alone in my suffering forever.
I want to find places I can go where I can meet those in my age range and just hang out or meet people. Whether it be things that interest me, or something new. Just good places to socialize.
(TL;DR) What can I do to more easily connect with and make friends with people in my age group, if not as a whole? How do I learn to give vulnerability a chance so I can stop being so lonely?