I'll be 65 this year. I guess I'm in denial, because I don't consider myself an old geezer either, lol.
If I rode 20 mph on my commute, I'd be a dead man. I could bet that I'd be sideswiped or hit from behind. I'd also be hearing a whole lot of "Get off the road!"
Traffic here is VERY congested. When it clears along my commute to work, the drivers are playing "catch up". To claim the lane, I need to be travelling at the speed limit or 5 mph over. Any slower, and the safest place is the short stretches of bike lane or the sidewalk.
I had an impatient Mercedes van overtake me as I left the traffic light on a two-lane road. The speed limit was 25 mph, I was accelerating towards 30 mph, and the van must've topped at least 40 mph
I have hit 43 mph for brief moments on my commute. It is not a speed I like to be travelling at. Travelling at 25 mph-30 mph in traffic is comfortable for me.