>>16225429Is it even possible not to know how to ride a bike?
The only thing you need to learn while riding a bike as a kid is to trust the physics and hope that you can move fast enough that you do not fall, which can be even less than a walking speed.
Such incompetence and lack of courage is something only kids can muster, it comes with age and experience. Even if you never rode a bike, you most likely would be able to ride one anyway.
It's similar with swimming, although a lot of swimming techniques are a bit harder than the others.
