#1, My dd's pitching coach wouldn't let her throw the movement pitches till she was 12 and kept it very limited till she was 14. Fast ball, change up and peel drop was it. Her coach was concerned that the movement pitches put too much stress on her arm bones and growth plates and other stuff I don't know anything about. DD is now 16, throws some pretty freaky stuff (hence my screen name), sometimes throws 3 games in a weekend and has never had any issues with her pitching parts.