BUT: I did finish up my century after all.
The only problem is that my average speed was about 4 miles per hour, since it took me over a day to complete it!
Back out on the bikes today at 8AM with my training buddy David. We did 26.4 miles at 17.3 mph rolling average, PLUS changed 2 rear flats (one apiece). It took me eleven minutes to change a rear flat - at least my speed is improving on tire-changing!
THEN with a superhuman effort we completed 2 miles on the track. 10:13 and 10:44. That's a pretty brisk pace for me with my old achy thighs today!
OK, maybe I don't suck as badly as I thought. It sure helped that it was a perfect day with a crystal clear blue sky today. I'm sure glad that I didn't have to change that flat in the pouring rain yesterday. Thanks for the reassurance, folks!