First Timer- is to soon

There is a sprint triathlon August 7th I have signed up for and I want to make sure it makes some sense for me to do the event. I have exercised three times per week for a number of years with occasional periods of increased intensity. This basically includes running, step machines etc. I decided to do a sprint triathlon three weeks ago as I am tired of playing golf and would like to lose some weight. Monday I swam 1000 yards in the pool (500 without stopping) and I ran 3 miles today in about 24 or 25 minutes. My bicycling has been very limted and basically includes riding a bike at the Y for 30 minutes at a time. I have not had a day yet where I have combined events. I swam competitively in my teen years and have run 10K's before but this was more than ten years ago. This is basically the last event close to where I live that fits in my schedule for 2004. Should I go and do this race and just pace myself or should I just wait until 2005. Personally, I am ready to dive in an get started now and then make more formal plans of preparing for 2005. Any advice is appreciated.

One last question from beginner- I am not quite ready to don a Speedo but would like to know if there something more modest that I could swim, bike and run in.