We feel she was blessed with hair like that, so it's important to share that blessing with others who aren't. So many children have lost their hair during their battle with cancer, and giving a gift like this makes them feel pretty again or makes them even feel "normal" again. She can always grow her hair again, but in all honesty, she may want to continue donating her hair to these children because she feels good about it. If she ever wants to keep her long hair, she certainly can, as well.
