I am fairly new to riding, but I found that taking the Motorcycle Safety Foundation class helped my confidence out and also increased my knowledge.
I thought about getting at 600 sport bike, but I knew I would out grow it, so I jumped on a good deal on a 900. I do not think it is too powerful, just as long as you can handle not gasing it.
I feel really confortable on it now. What ever you decide to do, just make sure you do it as safe as possible.