I just started cycling this year, and I am 47. I am up to 50 and 60 mile bike rides and will do the MS 150 in a few weeks. I ride twice a week, and my average is 14.3-15.5, depending on the length of the ride.

Having said this, I started out cycling in great shape from 20 years of weights and cardio. For me, it was simply a matter of learning to ride a road bike, getting my butt used to the saddle for long periods of time and tweaking my nutrition a bit.