In the image Shawn provided, you'll see her hands come forward with her step. It's really tough to get it right, but those hands should stay back, creating a stretch. At least that's what our hitting coach and many here say. My DD struggles with it too.
Also, the video was in rapid fire mode. I prefer batting practice to be a little more disciplined. Get into your stance, take your time. Her feet were in different starting positions almost every pitch.