Sounds like a great way to learn and have some fun to me. This is sorta what I did when I was teaching myself mandolin (very much still an ongoing process). Some folks I didn't know were looking for a mandolin player, and I was upfront about being a noob, and just went and jammed with them. It turned out I sorta knew their drummer, but at any rate see if it clicks in your case, and if so run with it. I've probably played a dozen or so gigs with the hippie band in my case. Had a ton of fun.

Break a leg!