queen of procrastination

Just do it!

Even if you end out walking the run, you'll have an idea of what's going on with your training.  Think of it as a 3 sport brick with transition practice thrown in that you'll be doing with a bunch of other people. Better DFL, then DNF, which is better then DNS.

A great piece of advice I was once given, "I don't regret the things I've done, rather the things I haven't done".  Best of luck to you.

First, calm yourself.  You will have plenty of company when you get there.  A big portion of the field is usually comprised of beginners many of who will be in the same boat more or less as you.  Just go ahead and do it.  Don't try to compete with anyone ... pace yourself, run your race and you should be fine.  Take your time to change in the transition areas; that is usually the worst part for beginners.  And remember that that putting on a jersey on a wet torso is almost impossible.  I you have to wear a top, wear it in the swim ... it will save you time and aggravation. 

Oh, and have a great first triathlon!  :-) 

In the water, take it easy, think that you are in a big pool with a couple of friends swimming on your side, if you got tired swimming, do slower strokes and breath deeply.

Don't go too hard on the bike, so you'll have legs for the run.  And another advise, before finishing the bike, spin at 100+ with an easy gear, you will have good legs for the run.

And in the run, pace your self, if you normally do 8 minute miles training, most of the time, you can't maintain that pace in a tri, so don't push yourself too hard.

And most important of all, HAVE FUN!