I can imagine it is very difficult for her. It is not just hormonal. I am a holistic doctor who focuses on women's issues and I have worked with many tweens. She needs your emotional support and please do not have her use tampons; too traumatic. Have her pick out organic pads without dioxin; bleach used in feminine care products creates dioxin which is linked to many types of cancer.
If she has a lot of cramps that means she may be deficient in essential fatty acids (fish oil, flax seed, avocado, olive oil) and B complexes; especially B6.
And in response to the last email, do not put your child on birth control pills. It messes up the feedback loop between the anterior-pituitary gland and the reproductive organs. What this means, is when women go off the pill and want to have a child, many women have problems, this means infertility. I have worked with many women with infertility which has been realted to this feed-back loop problems ccaused by the use of the pill. This is real and well researched and documented. The worst part is that if any woman has been on birth control for longer than 10 years, she may never be able to stabilize the feed-back loop and may have hormonal problems for the rest of her life. It makes for an exceptionally diffcult menopause when this system is malfunctioning. Also, the pill blocks the bodies absorption of B6, which makes for even more difficlut menses.
I wish you the best!