Congrats on the ride and birthday. I've only been riding a bit less than 2 years and not as serious as many. I did ride my age(plus a few) around my 61st birthday in late July, which was my longest ride at the time. Assuming I keep riding regularly, I figure I can keep it up for a number of years. For me, enjoying my time on the bike is more important than how many miles I put in. As long as I'm having a good time, I'll keep doing it.