I haven't done a ride longer than 8 miles in about 2 years. The total of this trip was about 46 miles.
There 'ya go, most likely. Fit could be another issue. Plus, if you're eight years older than your last big cycling memory, you should know that older age complicates things with the body and you can't just saddle up for a lengthy jaunt like before without paying the price. See a cycling doctor for a professional opinion.