I think a 2 year old would have no problem riding one of these. Ok, maybe 3 years old might be better.
Certainly, by 5 years, I think they would be able to safely come along for a e-ride with mom and or dad on the trail.
When did your spawn start riding a skateboard properly?
Mine was about 5 or 6 when he learened how to keep his momentum in a half pipe.
Idk how much these cost, but they look fun as hell, and seem like they could be a great, and much safer way to get your kids into the sport.