I started playing open mics just to get my feet wet in the performing aspect of being in front of people. That can be nerve racking the first few times! After months of playing, and then eventually hosting open mics, I built relationships with a number of musicians. There was a local band that lost their frontman and was looking for a replacement, so I was offered that slot.
I wasn't even looking for a band and I "fell" into one just by being out there performing on my own, and appreciating fantastic music that others brought.

The point is, you have to put yourself out there as much as possible. Maybe consider hosting your own open mic at a local coffee shop. There is a lot of info online about hosting open mics. If you stick with it, you will meet some very talented musicians and doors will open.

I'm glad to see you're doing this so young. I was in my late 40's when I got around to playing live music and I've been playing since I was 12.

Best Wishes!
Troy