Practicing up a lot before you start to compete is a bit like cleaning up before you take a bath.
You could spend years in the effort to stumble upon proper techniques, simple tips and tricks, and even the best equipment choices on your own -- or you can start to participate NOW, and get all that information/experience and a lot more in a season of shooting. And the more involved you get, the more people you meet, the more advice you seek out -- the faster you'll climb that learning curve.
I don't care what kind of shooting discipline you're entering, the idea that you'll could get "good enough" on your own to impress anyone or "earn" acceptance is a myth. And it is a myth as well that you have any need to. The only thing that's going to impress anyone is how safe you are.
You won't set the world on fire (win matches) as a novice. There wouldn't be any value in entering competition if you could! The sooner you get involved, the sooner you work through the awkward newbie stage and learn the ropes.
And, lastly, the great thing about shooting competitions is that "beating" anyone else is really pretty far from the point. You shoot against YOURSELF. You shoot to better your past performance. Winning anything is pretty secondary to your individual achievement. The greatest skill to learn is to be able to evaluate your own performance accurately and measure progress. Competition is really just a great framework for measuring your personal accomplishment.
Go, get involved, have FUN!
-Sam