I used to live in Chicago and SF. I’ve since moved to rural Tennessee. I can tell you everyone, including my kids, now have learned to drive our tractor. Granted I’m with them, but we had my 4-5 year old moving hay and they were helping me change oil.
I understand the concern, but everyone learns through doing. There’s definitely danger in that, and you should try to limit risk. At the same time; not teaching them is also high risk in that environment, as they’ll do it anyway with friends later.