i started riding street at age 18 on my first street bike (having extensive dirt background). it was a yamaha YSR50, would now be considered a pocket bike. i was probably the laughing stock of my town, rolling a max 55 mph downhill. but back then i was scared that i wouldn't be able to handle a 250! i rode that thing for a year before upgrading to a 250, which i managed to drop the very first day i owned it in front of all my friends in the taco bell parking lot (they had to pick it up for me, mortifying). after a year of riding, i sold that one to go to school. a few years passed and i decided to get back into riding. what did i buy? another 250. i was scared i couldn't handle a 600, even though my friends said i could. i rode that for another year before trading it up for the 636 i have today. i was still scared the day i picked up the 636 that i couldn't handle it. i finally took the MSF course with this bike and realized i shoulda done that way sooner.
moral of the story: i am still alive today, and i contribute that to starting small (very small) and not listening to what others think.
1HBC, do whatcha gotta do. just keep your head in check. make sure it's what is right for you. good luck finding what you are looking for. and go green, kawis are superior bikes in any year.