Freezing in a swimsuit

So this Saturday is the Beaver Freezer triathlon, which I committed to a few months back and for which I never had time to seriously train. It's scary ... I don't know if my swim time is accurate or not, so I may be getting in people's way in the lanes, I've got tons of shopping to do to prepare (shoelaces, swimsuit, windbreaker, sports drinks, CO2 inflator, goo, etc.), I tend to hurt myself when I run (knees, leg flexibility), I have to hydrate and get used to getting up early, and do it all this week (when I've got ten million other things to do), .... and I just plain haven't entered a competitive sport for years. It's scary. Exciting, but scary.