nobody outgrows a ninja 250. sorry, it just doesn't happen. it just forces people to work on their skills more. a ninja 250 is a GREAT bike to start out on, regardless of height/weight unless you're like 350+ lbs lol. its not only a great bike to start out on, but its also a great bike to brush up on and improve your technical skills as well.
to OP: you need to get a bike that has less than 90 hp, end of discussion. the reason for this is because when you're on a bike, its very easy to get in over your head and you dont have the safety nets that you have when in a car. also, everything you think you know about driving gets thrown out the window when you get on a bike. what may be natural or instinctive in a car will get you killed on a bike if you're caught in a bad situation.
there's a lot more to trying to pick out a good starting bike than just hp, torque, and overall weight. you also have to pay attention to rider position, center of gravity, maintenance, rake/trail (they do affect high speed maneuvers as well as low speed), and abundance of parts (you WILL drop it, the question is:when).
an sv560 is a GREAT bike to start out on for all the points listed above not only in this thread but also in other threads. the ninja 250 is also a great bike to start out on, as is the ninja 500.
any idiot can go fast in a straight line, but most people cant take corners for shit whether its a car or bike. a ninja 250 will easily give the 2.3 mustang turbo a run for its money from light to light as well as in the twisties, so dont think you're lacking for anything when you look at anything other than an r6 (a bad choice) or a gixxer (also a bad choice).