It's Not Just You
Feeling nervous at that first (or second, or 20th) open mike? You're not alone.
So are, roughly, all of the other performers. They're just more practiced at dealing with that.
Case in point. I've been playing for... argh... 35 years. And performing for, let's say, 30. But I'm currently in the leading-up-to-a-gig phase, and I, uh, don't handle it flawlessly.
Read about my nerdiness, and maybe feel better about yours. Then go out and play.