Most people in the US don't start dancing until their teens or 20's. I didn't start until I was 18, I'm now 20 and will be just starting to compete next year and I plan on going all the way *fingers crossed, knock on wood, rubs the rabbit foot*.
I'm not sure how long you've been dancing so my advice might be a bit useless but my advice is to just enjoy your dancing and lessons right now and when you're ready to compete, go for it. But don't worry about competitions too soon or you'll burn out. Good luck!
~LB
The question everyone should ask themselves before starting each day: Quo Vatamus