I want a new dirtbike?

i am about 4'10'' and in need of a dirtbike? what should i get if i am mostly going to be doing trail riding and going in my yard? also remember i am not a big rich kid.should i choose between a ktm 85, cr 80r, klx140, crf 150f, crf100f or any other bikes that i have not said. all answers would be appreciated thanks...also i am a smaller rider as i have mentioned...