my 9 y/o is having some noob gains, the past 2 days he's been averaging 12mph after starting in March at about 8mph. He hadn't been riding much during the summer because he isn't really into it (despite begging for, and receiving, a Felt road bike), but I've decided the exercise is more important than the future ramifications of him hating bikes lol Plus, it's basically going to be his phys ed for the school year since he's on a hybrid attendance model.
I am not exaggerating when I say that kids in my neighborhood, of which there are many, hardly get near the recommended amount of exercise. They'll get on their bikes to ride a few hundred feet to the next congregating point and stand around doing whatever they do lol Of course, exercise isn't important to kids because it isn't important to adults, a couple of folks do go on walks around our neighborhood loop but for the most part adults aren't out with their kids. Hopefully my son will look back and be glad that dad takes an hour to ride around with him.