You're not even sixty. I know we all age at different rates, but you should be able to keep your strength through your sixties. I remember one winter day when I was xc skiing and I left another, much younger and very fit, skier, far behind and exhausted. I had just turned sixty four, and some of it was technique, but still I didn't feel my age.

I'm twelve years older now and not as fast, Low gears help.

I don't see my self geting an E_bike since physical exercise is one of my reasons for cycling; There are enough labor saving devices already, the challenge is to stay active.