My boy, Gus is 11 now. One morning when he was 4 1/2 or so he came and woke me up and said he didn't need his training wheels anymore. He led me out to between the house and garage where he had his bicycle turned wheels up resting on the seat and handle bars with tools all laid out. I asked him if he was sure and he said he was so I took 'em off. He just took off riding like an old pro. Only thing was stopping which he took care of by running off in neighbors front yards where he'd crash-land, then saddle-up and take off again. Wasn't long before he figured the brakes out.
When I worked on a dude ranch in Jackson Hole, one boy was so small that I led his horse instead of allowing him to ride by himself. He would say quite often, "Can I pleeeeeaaaaase have the leash?" :wink: