[Christ]

Sprockets are easy enough to come by for the rear wheel if you need to slow it down. Or, you can limit throttle input using the controller in most cases. Or just physically limit throttle until you're comfortable with above mentioned particularly small child giving it "everything".

When we bought my son a JD electric tractor, we limited him to 1st speed operation for all of 20 minutes before I was comfortable with him steering, etc. He now uses 1st speed for intricate maneuvers and 2nd speed for general operation. Talented 3 year old, he is.