Hi Rita! It would cheer you up if you saw the video of my first comp. Talk about a train wreck!
What you've experienced is completely normal for a first comp. Don't forget, you're competing against dancers at your level and they're all making mistakes too! I found it helpful to go through my routine in lessons over and over, with a "no stopping" rule, no matter what mistakes I make. You can learn not to react visibly to a mistake and how to recover and get back to your routine quickly. Since mistakes are just part of the game, that's a more reasonable goal than expecting not to make any mistakes.
Good luck at your next comp!
The nerves will get less with experience, too.