If she is an accomplished rider, she'll be comfortable on most bikes. I'm 5 ft 2 and the height thing doesn't bother me anymore. And, as someone mentioned, you can always change out the dogbones to lower it a bit if needed. Some of the older 600s were lower than the newer ones (i.e. Honda 600 f3, Kawasaki 600 "e" i think it was). She might get bored quickly with the 250/300 Ninja's. Good luck. Mary