I can relate! Someone who is very dear to me suggested we go to a one-day pottery class and the idea had never entered my mind. I actually ended up loving it. We're both introverts, as well, and she enjoys doing things that don't require other people (she likes to surf, as well). There's something about doing something physical by yourself (that isn't exercising) that's creative that I really like, but before the class, I hadn't realized it.
I actually play instruments, as well, but this feels totally different and almost stimulates a different part of my brain. I was much more relaxed doing pottery and I saw instant results that I could track whether I was doing something right or wrong (even though the "right" and "wrong" was driven by my own personal idea of them).
Do you think you'll end up sharing any of your pieces to the public?