In reading my comments again I can see the confusion (probably should’ve been more careful using the word “size”). I meant to imply that the size advantage for someone in football is not necessarily an advantage in karting. A 6′ 0″ 150 lb kid playing football against a 5′ 0″ 100 lb kid is likely going to have an advantage or at the very least create a safety concern which should be addressed.
In karting, a 150 lb person will be on the same level as a 100 lb person, provided the weight advantage is evened out so the the 50 lb difference becomes a 0 lb difference. The primary component of winning at that point becomes the skill of the driver. If a person is less skilled they will be at the back of the pack (out of harms way) until they become more skilled. I believe “skill” is not necessarily something I would associate with age and that “weight” should be the differentiator. :)