I can say something about this from the kid's perspective. When I was 14 or 15 or so, my dad would let me drive (always with him in the ca on country backroads, 25 mph dirt roads and the like, with little to no other traffic. Mostly it was roads going through orchards, and the only other traffic was farmers driving slow moving tractors was about all you had to contend with.
We'd be going down one of these roads on the way to somewhere or the other and he'd say "You wanna drive?", and of course I'd say "sure". Then he'd pull over and let me drive. He had a hard time holding his tongue as I grinded the gears and forgot to remove the parking brake and all the things new drivers do, but for the most part he would just sit there and let me do my thing. One time I veered too far to the right for some reason and ran over a big bump on the shoulder of the road, so he told me to "stop" and he walked me back down the road the way we had come from, showing me step by step the wheel tracks (in the dirt road) and how I'd veered at just the right spot to hit the bump at the worse possible spot. It was pretty revealing and a good lesson to always pay attention. I still remember in fact. (I still have no idea why I did that! It might be like when I ride my Mtn bike these days, if I stare at a rock, I am almost sure to run over it and get thrown off the bike. I have learned the hard way when Mt Biking to always look at the path where you want to go, not at obstacles you want to avoid.)
By the time I took the driver's education classes, I already knew how to drive, and had no problem. My dad didn't like the way the instructors told me how to make a left hand turn, so he re-learned me on that topic.
Not sure it this all helps or is even applicable in these modern days where the biggest problem seems to be distracted driving, but it all worked out for me.