This is not at all uncommon among girls that grow up playing in the younger age groups where coaches constantly encourage "pulling everything" so that they can get the batter on base because the younger girls can't field and throw the ball all the way across the field.
Here are a couple of quick tips without changing any kind of mechanics:
1. If she is standing in the back of the box (towards umpire), move her to the very front of the box so she can keep her aggressiveness and keep the ball fair. Many girls just stand in the foot steps of the previous batters, and most girls are intimdated and stand in the back of the box because they can't handle the speed.
2. If she is crowding the plate, she's begging the pitchers to throw her inside so back her away from the plate so that she'll get a better mixture of pitches.