I believe first stage jitters are normal. The first stage is when you worry on your draw, grip, your sights, your flinch, your transitions, getting DQ'd etc,.
I get over it by just not expecting too much from myself and just letting things happen. When the RO says load and make ready, All I focus on and think about is where the first port is and the number of boards and plates in it. the rest follows.
Normally, the first stage is always my best stage. I always blow it on the last stages due to fatigue, boredom and over confidence.
End of the day, I got to do what I enjoy doing and I look forward to next week.