My son, who turned 15 today, raced karts from age 8 until 13, at which point he was just oo physically big to be competitive at 6'+ and over 200lbs, in a minimum weight class. So a bone got thrown out: straight A's 2 marking periods in a row and a 3-day Skip Barber school would be the reward. Due to a major football injury last fall that had him immobilzed on the couch with school via home instruction, he did good and made it happen.
So, back in April at 14, he got to do a 3-day MX-5 racing school at Laguna over Spring break. Zero issues at all, and with all the car control learned with the kart, he was among the most competent students there.
We are working towards going through the SCCA 15-year old licensing process; he "audited" a Drivers School earlier this month as he was 12 days short of being 15.
It helps that size and looks wise, along with how he carries himself he could easily pass for 18 or 19. For better or worse other's perception of age and maturity goes a long way.