I've got a similar deal going with my 14 year old son. I would basically just back it off until she can draw it without undue strain. And then just measure the pull weight so you can get arrows spined properly. In our case, backing off a Fred Bear Elementfour turns brought the pull down about ten pounds. Also brought arrow speed down about 30 fps.

Bad thing about all this is that, within a month or two, she can probably pull more weight - maybe an increase sufficient to require a stiffer arrow spine. Oftentimes, you can just decrease point weight an get the proper spine for the same arrow with a bow 5 lbs. heavier in draw weight.