I just happened by this thread, since I gave up on my idea of doing a tri a few months ago.
But I can relate to the competitive thing. I have been a type A obsessive type with work and school all of my life. In fact, pretty much with everything. I will never forget the time maybe about 12 years ago when the mother of one of my son's classmates told me she was shocked when she found out that I had a full time job and I also worked as a fitness instructor. She told me that she figured I was someone who just sat at home and made myself look "put together" all of the time. Huh?? Like a working mom can't be organized and "put together?" But, when I reflected, I understood what she meant. I don't do things if I can't be good at them. Well, cycling changed all that. It also has caused me to slow down and re evaluate (well, and getting older). Most of the people I ride with ride a little slower than me. That makes me feel "good" but sometimes frustrated. When I ride with my husband, he pushes me at times and when my average goes up, I feel really good. But then some woman flies by me on the road and it sends me into a tailspin. I train too much and then I get sick or tired or burned out. So last year, I decided if it wasn't going to be fun, I couldn't continue. I found a group to ride with that sort of rides at my middle of the road speed-- 15-16 mph average. I have found it hard to find people who ride at my speed. Most are either way to slow or way too fast for me to enjoy riding with.
OK, I am rambling, but I have found out when cycling starts to feel like work, it's time to back off and go do something else. That's why I didn't start training for a tri. I am a slow 10 min. mile runner and I can barely swim. There are not enough hours in the day for me to try and improve all that and still live a somewhat balanced life.