My 15 y/o daughter has been asked to a mixed sleepover with no parent present and mixed sexes, other than the occasional argument she never causes too much trouble and hasn't had any relationships with boys other than friends. Don't know the whole group of friends (there will be 4 girls and 3 or 4 boys) but as far as I can tell they're good kids, feels wrong saying yes but she hasn't ever given me a reason to expect anything wrong to happen. What should I do?