It not age but height. I believe it's 48 inches minimum. They have kids races that are separate from adult races
Height divides you into the slower kid's karts (under 48"?) and the faster adult karts (over 48"). Each race is either fast karts or slow karts, not mixed.
For everyone
Kids race with everyone of all ages
There are adults and kids, but the grouping is by height not age. Minimum height is 48".
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