I'm 66. Been riding bikes since, well the late '50's. Riding is the only form of exercise I actually enjoy. When I was 12, I rode a 40 pound J.C.Higgins paperboy bike 65 miles in one day. Don't remember it being that big a deal. Still enjoy riding. Mostly on level ground these days. .
Later, in my 30's, I was pretty damn fast on the bike. Racing/drafting...all cool.
Still have 5 bikes, even an old Schwinn like when I was a kid. Keep riding, it gives you a better outlook on life, which is hard these days.