OP: Average speed has too many variables to act as a valid basis for comparison (This may have been covered)
And because it's totally irrelevant: I do keep track of my speed on a set course to gauge performance. umd's numbers look realistic. I'm 43 and don't race in any "Cat" but ride about 5 times per week. Cycling and occasional TT / racing is a way to stay in shape for ski season.
kaNUK