I also said I wouldn't allow a sleepover at 17. Call it any kind of party you want, hold it any time of the day or night, I still think many are too immature to handle it at 17. Yes, it depends on the child how mature they may be but these days, some of the PARENTS don't even act maturely. Research has shown that children need, and want, guidelines and boundaries. Some may ask, not because they really want to go, but to test the waters or because their best friend is standing next to them. Peer pressure is very powerful and secretly they may be hoping for a "no" answer.
Even if I err on the side of caution and not allow her to go, missing one party is not going to kill her. But going to that party just may.....