If fitness is an attribute of youth, then yes. I'm 66 and walked uphill to a neighbors house last night, probably 20 feet of elevation change over a 100 foot walk. I was happy after walking it briskly, no sign of doing anything physical was apparent. If cycling isn't a fountain of youth, it is at least conduit for maintaining mobility.
It's winter and cycling has been quite sporadic over the last month, maybe 3-4 rides during the last 30 days. Probably 10-12 days of ice skating over the last month to supplement fitness, I was amazed at residual fitness shown on my first ride day before yesterday. So fun to feel the wind and be able to ride fast and climb still. Taking up serious cycling in 1975 was certainly a gift.