It's wonderful that she is so interested and is doing so well with her projects! But if you have certain fabrics that you don't want her to cut up, you should tell her that. Either limit what she can use or help her find a way to acquire her own. Thrift shops are a good idea. There are also sale sections of on-line shops. Surely there must be chores where she can earn extra money to buy her own. Good luck with her wonderful talents!