My son is 12 and has been riding a 2003 YZ 125 for almost a year. He likes riding track but has decided he doesn't really want to race MX. He may race some cross county and ride local MX tracks but mainly focus on trails. He is not going to be happy with a mellow trail bike but I think he needs something with more versatile power and can still work on the track. I don't know if a engine upgrade on the 125 and suspension would work or I'd I need to start looking at other bikes.