TL;DR: randonneurs ride in timed, regulated road-coarse events that start at 200 km and work up to a traditional distance of 1200 km (and beyond). It's endurance cycling and ... the kicker ... it's full of "old" people (because they seem to have the wisdom and gumption to ride smart and long). In my local club, there are definitely young riders in their 20s and 30s but the most prolific riders are over 50 and the top two are gentlemen in their 70s. "Top" as measured by most events ridden in a year and most event mileage in a year. Their average speeds put young riders to shame more often than not.
Slow and steady wins the race, for values of "race" greater than 200 km. ;-) There are local clubs all over the USA, Canada, Europe, and everywhere.
Anyways, not everyone knows about the sport of randonneuring so I just wanted to share in the context of inspiration, no-age-limits cycling -- it dates back to the 1890s and I personally think its community and values are better than regular competitive road or mountain biking, having done all of the above. Ride safe.