Quick, /a/! She wants to be a grown up woman, what do we do?
Inform her that the time will come in some number of years. For now, she should enjoy her childhood while it lasts. The lass can take it from a grown-up: she'd regret growing up too fast.
Make her listen to classical music
Provide her the resources and support she needs so that she can grow into a well-respected and well-rounded human being