Seems like you did just fine! You are not as bad as your worst time out, you aren't as good as your best time out either.
Playing weekly events I tried to hit 85-90% of my best performance. Big events I tried to hit between 90-95%+. You are unlikely to be able to play very near your peak every week, got to rebuild some too. Not to say you shouldn't compete every week or even several times a week, but don't expect outstanding performances every time.
As has already been said, unless you brought somebody with you nobody cares about your performance but you. Focus on yourself. Could be a lot worse, I started competing at circle track stock car racing in my teens. A few thousand people were watching my first efforts and since the race often had to be stopped to untangle things everybody knew who the goat was! That is goat too, not GOAT.
If at all possible, do bring somebody with you, ideally another competitor. Your mindset will be better when you have someone to talk to. Events are more than twice the fun when you share the experience with someone else. I hadn't competed for a year when I went to an event. I rounded up a couple people to go with me mainly so I had somebody to laugh with about my dumb mistakes on the way home. I relaxed and chatted on the way to the event, celebrated my victory on the way home! Just a phase of the moon thing. I went in not expecting much and didn't put much pressure on myself. When things started off going pretty well I turned up the heat!
If you compete regularly sometimes it will be your time to shine. The first time is the hardest. If you go often enough you will be seen as a regular at the event and one of the in crowd. It is a plus to be friendly with the other competitors, particularly the big dogs. Don't let false modesty, or real modesty for that matter, get in the way of your goals. You will have to pay your dues like everyone but remember you are moving towards a goal and never deny that. You don't have to brag or boast but you are there to win. If not now, soon.
As already mentioned, you did fine for the first time out. You also did an excellent job writing up your experience.
Hu