You're in the wrong section....this is for [bi]cycling...there's another section for motorcycles....
What everyone else, and I, are going to say is that first of all you should take a MSF course. They'll teach you everything you need to know about riding and staying safe while riding.
As for your first bike, the Ninja 250 is a great choice. You might also want to look at the Ninja 500 or Suzuki GS500. As a beginner you don't want to start out on anything bigger than those, especially the sporty 600cc's.
The best thing to do is go to a dealer and sit on them, see which one feels best.