I went to one daughter's hen night and found it a major embarrasment then I went to my youngest's when she went clay pidgeon shooting, followed by a cream tea then on for a nice meal. After this was a chance for we oldies to leave and the youngsters to go clubbing. It was great fun and I hope yours is as good.
Perhaps you could wear a long pink jumper (long enough to hide bits if necessary) or a long pink shirt over your tights. The latter might be cooler for a night club. Or you could go as a card, making a removable card to take off when you need to sit down, wearing matching pretty trousers and top underneath.
Actually I like your idea of the Cheshire Cat better but think you should wear a tutu. Why not? You are only 57 after all, a mere youngster. 
have a great time.