Uh, no. Adam Petty and Austin were in real race cars earlier than age 17.
Oh, yu are are talking about faux racecar drivers...
ND was talking about the people who are legends, whose names are whispered---Alex Zanardi, Michael Schumaker, Kimi, even Nascar driver Juan Pablo Montoya. He went to Nascar to collect a cheque, as he was pissed he didn't get a chance to drive for Ferrari. All of the ex-F1 drivers, and possibly Indy Car drivers started in carts...as those are real tracks---or road racers.
True stock car racing is found in Germany's DTM.