What should i get rmz250 or yz125 or maybe yz250?

hi i am 14 5,8 120 pounds i dont race yet but maybe in the future i ride in my own motocross track with alot of jumps and i am coming of a ttr230 i want way better suspentoin an more power but i cant decied what i want i like 4 strokes because there dependable and get good fuel economy and i live on a farm so chase cows with my bike but i like 2 stokes because if it blowes up its not 3000 grand to rebuild it!!!!