I am looking at getting a KX-110 for my almost 7 year old son. Now this would be his first bike but he does have an ATC-70 that he has learned how to shift and control so after reading the reviews I thought the KX would be the way to go because size wise it fits him better then the xr-50 or pw-50 but I don't want to spoil this experience for him by getting too much bike. Any suggestions?