No, certainly not. I'm advocating learning to compete with and develop the fastball, through long-toss and sound mechanical training. The curveball age 13/14 is a good pitch to mix in since it is the equivalent of a changeup anyway. Go and and use the change just remember you will not master it at the h.s. level. I don't know any large college coaches that recruit a fastball/change unless the fastball is 90+. They are looking for a fastball/breaking pitch and be forwarned the slider and especially the splitter are arm killers.