If she ask for help and the instructor can't help her at that time. Tell her you are trying to catch up too and when you get a chance you'll help her or she can wait for teacher. That's what I do even at work when Im in the middle of doing something and we have a co-worker who does the same thing and it causes you to lose your train of thought. I understand how you feel. But maybe if she knows you don't want to fall behind she'll understand. Good luck.