I'm 68, 85kg. I had a bike for a few years when I was 10-12, then puberty saw me outgrow it and my brothers got it. Never had another bike until I was 42 and I bought the wrong size of City bike (M when I should have got an L). I put up with it for 12 years! Then bought a Cruiser bike in 2005, correct size this time. I loved that bike and was out some part of most days. In 2008, I discovered that mtb was a thing and thought it was just exactly what I was looking for. I bought an XC hardtail, a year later an XC FS, and then a year after that All Mountain FS. Went to the Alps in 2012 with a group of mtb buddies and discovered new definitions for "steep" and "rough"! I was going on mtb skills courses at the rate of at least one per year but didn't feel to be getting better as fast as I wanted to. But I was getting fitter and faster! I felt like Superman at 63, but then I peaked when arthritis in the knees and hands started to affect me. Slowly I dropped out of group rides, slowly my distances per ride fell away and the gaps between rides got bigger, from riding every day to three day gaps. By 67 I was down to one 10-mile ride every 3-4 days and that was on a carbon FS bike with 1x12 and a 30t front ring, kitted out with pain killing gels for the knees and all sorts of other stuff. I had seen emtbs for a few years, but was reluctant to even try one, but I was also reluctant to keep fading away on mtb!
In Jan'19 I bought an emtb! (I was 67 then). WOW!!!

It was like me again, but on a really good day.
I had a couple of firsts last Saturday. It was the first time for five years that I had ridden on consecutive days and the first time for about the same length of time that I had ridden 30 off road miles in one day. I should have bought a bigger battery!
I feel reborn, EMTBs are ACE!