Some parents might not mind what your daughter is doing, but if you mind, that's what should matter the most in your home.
I can tell you from experience that 18-year-olds today do exactly what they've always done: whatever they can get away with. When I ran your letter past my own 20-year-old, she rolled her eyes -- not over your daughter, but over you.
Please get some clarity about this and be prepared to communicate your position to your daughter.