I'm no expert at all, but one small thing I notice is that she's not on her power line at all. She's off to the right side of it. I can give you some drills that my dd was told to do that really helped her to get to where she was consistently on the power line every time.
+1 on this. Way off the power line.
She starts on the left side of the rubber and the stride foot lands WAY right. Some of this is caused by the glove swim (i.e. glove side going away from her body in a swim motion), not opening up fully and her body is trying to balance everything out. Two easy ways to fix this - use what some call a K or a W drill to help but the best way is pitching into her glove - so full motion but she has to release into her glove - she wont be able to do that and swim the glove like she is. Everything must go up and down together. I know WHY she does this - she is trying to generate power and speed - but it is inefficient and limited.
She also swings the ball WAY back on her backswing. Again she is doing it because she feels it generates more speed - but it can cause straight arm circles and timing issues (her arm has to constantly try to catch up with her lower body movement). Older pitchers can get away with this - but it is not ideal and if you can correct it now it is worth doing.
Cat does a nice tight glove side and is nice and straight on a power line (but she has a big backswing)- watch the glove side and the straight to the batter pitches:
Watch all the Hillhouse videos on Youtube and then buy his House of Pitching DVD's. He explains everything is a way that makes it really, really to understand.
The good news is that these are common issues in this age group and there is some excellent things going on. Plus she is a lefty which is an extra advantage.