In Ireland you get a 'provisional' tractor licence at 16, and you can keep renewing it. You can do a tractor test, but most people wait to pass their car test, when you automatically get a full tractor licence. I first drove on the road when I was twelve, but I certainly wouldn't want to see a system where that sort of thing was normal or acceptable, it's just too dangerous on the roads these days and machines are so much bigger and faster.
I always wanted to do that, but sadly never did . I suppose I was half afraid lads would nick bits off the tractor