My DD's pitching coach told her that as she progressed, she should eventually settle on 4 or 5 pitches that she felt comfortable with as her "normal" pitches, and that a plain straight fastball probably shouldn't be one of them at the older ages. Obviously he's big on placement, "never hit the red zone", which is the middle 50% of the plate, etc., but also on movement.
He hadn't shown her any new pitches for a while, but I think he showed her the rise-cut and she did well with it, so he got excited and showed her some kind of funky screwball-something else. They even went a half hour over, I think because he was enjoying it
I heard some announcer a year or 2 ago say that Cat Osterman very rarely throws a pitch that is a strike if not swung at, that almost every pitch she throws moves out of the strike zone. Unless of course it's obvious the batter is taking.
Donnie, does your DD handle the 18U pretty well. A buddy of mine is coaching a team that is going to play some 18U and some 16U this year, and he has asked me about mine playing some for them in 16U, but I'm not sure that's not too aggressive a move up (she could play 12U this year), and I don't think she is comfortable with it. We're going to start going to their winter workouts in a week or 2 (about all of them are playing HS ball), and maybe there she will see if she thinks she could play with them or not. I think she could, softball wise, but I'm not sure I want her in the dugout with a bunch of 15 and 16 year old girls (and maybe even 17)