What the hell!?

Ok, so I just signed up for the Escape from the Rock triathlon on Sept 11 before really finding out if I can honestly swim a half mile. Hey, I'm in good shape right? I used to swim a long time ago and it should be like riding a bike I think. There was a possibly of the event being full very soon so I decided to take a chance and sign up. I have three weeks to re-learn how to swim...that's plenty of time I'm sure...