i woud not by any means recomend starting on a 600cc. I have riden my friends 06 gsxr 600 and they are not in any way shape or form noob friendly. If you treasure your life, you will start smaller and work your way up. My advice:

Take MSF course
get all your gear (helmet, gloves, jacket, etc)
get a smaller bike such as ninja 250, or 500, or even something like a gs500f thats full fairing. www.sportbikes.net has some great info on there int he newbs section.

Most people only ridet here for bike for 6 months or so, and then sell it for what they paid for it, and move up.

O and FYI starting on a dirtbike means nothing. like was stated before, you learned howt o shift and were the location of things are. Past that its nowere the same.