I had my first race this weekend, too. This was my first race of the year and my first race ever. Mine was a college race (MWCCC) and I was in the C group, which is basically Cat 5. We were in Indiana (about an hour from where I go to school, actually) riding an 8-mile loop around a lake for a total of 20 miles. The weather was great for this time of year: around 40 degrees and sunny.
In some sort of mass confusion I ended up starting at the end of the pack. This one guy blew out his back tire not even 2 minutes into the race. I bet he was pissed! I had a feeling he pumped up the PSI a little too high. I was actually glad to be at the back of the pack at first because a couple times there was a strange mass-braking event and I couldn't see why. I was just waiting for a crash to happen.
The roads were winding with a few hills and lots of houses and trees around. In other words, visibility was crap. This and being in the back of the pack teamed up to do me in. What seemed like the back of one large group turned into the back of a trailing group and I never even saw it happen. It wasn't that late into the race and I was mad at myself because I knew I should have gotten closer to the front, so I decided to try to catch the lead group. I never caught up, but I did pass quite a few guys. During the last lap I finally caught up to a group of 4 or 5 guys and latched on back for a while. I decided I'd just hang with them and practice my victory sprint at the end. Well, they were only going about 18 at one point and some guy came riding by and said "work together to catch up." I decided to go chase him and try to beat him at the end. Not long after that he just stopped and went on the side of the road. That's when I realized that his number was a different color, so he must have been a B or A guy. I should have just let the 4-5 guys catch up with me again, but I went off by myself since I had been doing that the whole time.
I'm still not sure what place I got, but it couldn't have been that great. I got some really good training in, though. It's a shame, because I felt really good and fresh, but I just made the fatal mistake of being too far back. Hopefully I learned my lesson.