Another idea is just learn a few tunes that you really like and play those. Chances are, someone else will know them, and even if they don't, they'll pick them up after hearing them a few times.
In the same way, if you keep turnng up, you'll pick up some tunes that everyone else plays. This will change over time - tunes fall in and out of favour at random.
The important thing is to keep showing up, don't play loudly if you don't know the tune (but playing along quietly is a good way to learn new tunes) and above all, keep your ears open.
There's far too many tunes for anyone to know them all - part of the magic is that everyone knows different ones - don't be put off, just enjoy the music.
We all love it when new people get interested in the music - I'm sure people will be friendly and encouraging. Good luck with it!