Dude, make sure you read the rules thoughally. The position listed is only a prefered postion and it doenst actually effect performace at other positions. My best point guard is a small forward. It's only about stats and the position bit is really just to help new players.
If you just train outside defence and maybe jump shot next, you'll know exaclty what you're doing when it comes time to change. (I am training guards too, JS/OD/PS rotation right now)