What are the chances you're ever going to see any of those people who'll 'think you're mad' on a daily basis, or even again at all and if you do how will them 'thinking you're mad' affect your life in any way?
Also, people are far too worried about what other people think of them to care how fast or slow you walk.
I make it a matter of principle to do childish things when I feel like it, and I think it helps keep me young(er). Had to stop jumping over the fence when picking up my kids from preschool though after a teacher told me it made it harder for them to keep the kids from leaving the premises. Can't win them all!
In the United States of America. In 2019.
(I am not Black. Friends I trust have told me this.)
Spend some time on a treadmill, get used to walking faster, and you might find that people don't give you funny looks after all.
As a kid, I ran everywhere - even on errands. As an ambitious teen in uni, I walked very fast like I was stepping on hot coals until I got this girl who wasn't my "girlfriend" but we spent a lot of time together. Then she trained the speed-walking out of me. At first, I was always in front of her without realizing it. Then like a puppy on a leash, she'd tug me back until her speed became my normal walking speed.
10 years later, I still walk at that pace and run out of breath whenever I walk to get out of the hot sun.
As an adult, I'm expected to walk at a measured pace. There are times I'd want to just jump and start running but I can't, cos people would think I've gone mad, unless I have an excuse - rain.
So I'll say the gait speed of adults is more of a measure of how they have been walking for years.