What Have I Gotten Myself Into?

3 days until my first triathlon! I 've been really intimidated by it lately, and have pictured all kinds of awful scenarios of things that could go wrong. What if I crash my bike? What if a 70 year old woman passes me up? What if I'm one of the last people to finish? I think all these things and it makes me feel so discouraged I haven't been very motivated with training. It's interesting to see, though, because I think thats a behaviour pattern for me when I'm stressed. But, I didn''t commit to the triathlon thinking I would "win"- I just want to try it, and I will on Sunday morning, bright and early!
Oh, and tomorrow's my birthday!