the 250 would be better to learn on but might be under powered for your size. Might want to look into a 500r as it will have enough power and not scare the shit out of you like the 650 might. Last thing you want to do is get a bike and then end up being scared to ride it. It is always best to start out with a lower power bike and get used to it and the mechanics of riding before jumping up to the big league powerful street bike. Also not know your skill it is usually best to buy an older bike as they are easier to learn on and are more forgiving. Modern street bike are designed for a lot of power and experienced riders. Most newbies that buy a modern street bike wind up wrecking it and killing them selves within the first three months.