I raised 2 daughters so am somewhat knowledgeable?? about these things. If your 'gut' tells you 'NO', follow it--it is probably God talking to you. I have a feeling you aren't getting the whole story from your daughter. I would suggest that the 2 of you go somewhere that she won't throw a fit (take her out for hamburgers?) and explain that it is out of LOVE that you are not allowing her to ruin her life yaada, yadda, yadda. She may throw a fit after she gets home but probably not in public and it will give her some time to think about what you just told her. The other parents and kids will admire you for sticking to your guns.
Parenthood is NOT a popularity contest or to be your DD best friend, it is to protect and love until she is old enough and mature enough to make good decisions for herself. PRAY! Sue
Sue