Asrith-
Whatever its worth ;), my wife just started riding 2 months ago and I bought her a XR200. She is petite, 5'4" & 105 lbs, and she loves it. She learned on a TTR125L and was able to flat-foot it which made her very comfortable, but we were afraid she would out grow it too quickly, so we went with the XR.
After 5 rides she has been improving quickly and I think the XR is going to allow her plenty of room to grow as rider. The power and suspension are good and it just keeps truckin' along.
So you may want to consider a XR200, just my opinion. :)