I won't be the only crusty, the girl's family are going too, but we only know the birthday girl, not her friends or family so I can't even make a guess at how dressy or not it'll be.
All I know is that the v glam birthday girl is wearing a dress and killer heels, but then she often does.
I don't want to look mumsy, but nor do I want to look like I'm desperately pretending to be 18 again!
Any suggestions?