Nerve-wracking. Yes .... BUT ...
I'd do it again in a heartbeat (make that "palpitation" as during the Karelia Suite).
On our way home from the concert last night I was telling my husband about a few of the places where I'd gotten lost in a couple of the pieces. He stopped me and said to focus on the positive outcome, not the negative. Then he posed 2 questions: 1. Did I feel proud that I'd gotten up on the stage and performed this very difficult music. (answer: Yes) 2. Did I feel that I'd made progress in my playing over the past 3 months because of all my hard work. (answer: Yes)
Most importantly, besides feeling a sense of accomplishment, I have a feeling of camaraderie with the members of the orchestra. This is what makes the work, the struggle and all the anxiety worth while. This is why I will continue.