Viva, I too skipped the dedication in prayer. Noone really told me about it at the time, it was only later that I realised. :-) I WAS only 16.
I do know of two people that annulled their baptism. One was an older guy who was baptised way way back, and the other a 20 something chick. I have no idea what they used to get out of it. Would love to hear of a success story, and how they did it....