^ agree.
It's always harder to say no, than yes.
Let's face it, it sucks when your parent says no to something you will just "die" if you don't go to. I also remember feeling like a baby, not being allowed to do some things.
Kids are hard to deal with when they are upset about stuff like that, but if something happened at that party, and you don't know the parents, you would never forgive yourself.
I've seen parents ply kids with alcohol at parties too, and heard stories where porn was allowed to be played - so you really need to know who you are dealing with. There are predators out there too.