If I was going to practice for my first IDPA match, on my own, I think I would practice the Classifier Course of Fire.
http://www.idpa.com/classify1.asp
I don't believe in waiting until I'm better to start shooting competition. Start now, tell the people you're shooting with you are new and they will help you get started down the right path, correctly.
I don't know of any type of competition that doesn't want new shooters to grow their sport. They'll take in new shooters and work with you as you learn the game.