Well, you could get the trick candles, and have only some be that way. and instead of a cake have cupcakes and give one 2 each girl after you and only you has blown out the candles. AND you could talk about 16 of your fav moments in your life. These are just some I des that I hope will help you. I haven't put them to the test though because I have to wait for my Sweet 16 for a few years... Good Luck!
~Ella~