Hey Brian,
Congrats on your first gig. Don't worry about the mistakes--everyone makes them, and as scott says, most of the audiences never know unless you tell them. As for the jitters, anyone that says they don't get them is either lying or stoned out of their mind when they perform. Everyone, even us old guys, are somewhat apprehensive, especially when playing to a new audience. Granted, it gets easier, but even after more than 40 years, you still get the jitters to some minor degree.
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PSR-S950, TC Helicon Harmony-M, Digitech VR, Samson Q7, Sennheiser E855, Custom Console, and lots of other silly stuff!
K+E=W (Knowledge Plus Experience = Wisdom.)