My first performance was in a competition, so thankfully it was only the judge. I was playing Chopin's Op. 42 Waltz. I don't know if any of you are familiar, but you know that section near the end where it crescendos, and the left hand starts doing silly jumps? I could never get that down.
I go into the room and start playing. The easiest section, where the theme is introduce, I start making wrong notes. Slightly freaked, I keep playing, and it's good so far. Eventually, I get really really nervous, and my right leg starts shaking. This is the leg sitting on top of the pedal, so I unwittingly produce this flutter pedal effect that goes beautifully with the crescendo'd section, which I didn't make a single mistake on! And then I got a Superior rating!