You can either suffer with the thought of your children having sex, though one would hope with protection and common sense, or you can watch them bring children into the world when they are in no position, financially, emotionally, or mentally capable of being able to handle them.
The onus of raising those children will then fall upon you. You will go from being a parent of a teenager, to a parent of your children's children, leaving you with even less time to get along with the things you need to do for your life. I don't wish to raise children again after getting rid of the ones I already had.
LDH, it is a great thing that you have done for your teenage daughter, getting her invested in music and helping her to have someway of constructively channeling her energy. She probably realises the many disasters that come from teenagers having sex, the drama of boyfriends and girlfriends, unwanted pregnancies and the halting in the tracks of life that often occur as a result of having children at a young age.