I think what hung me up was having more than one race goal: I wanted to race tactically with the race leaders, and I also wanted to break 16 minutes. It became pretty obvious by the middle of the first mile that I would not be able to duke it out for first place, because there were two guys who just plain dropped me after the half-mile point (they finished under 15 minutes).
Once I was dropped, the race turned into a solo time trial, because the guys running behind me were too far back to bridge up and push me, and they were going slower than sub-16 pace. In the end, they came pretty close to catching me, but I was able to hang on to take 3rd place overall with a time of 16:08. Didn't quite meet either of my goals, but given the conditions, my time today bodes well for future races on flatter terrain and with warmer weather. I still have lots of work to do to get myself under 16, but I'm getting closer.