Is it too late to try to compete?

I'm still young to most people, in my teens, and I really like auto racing and NASCAR and I really love cars in general and I would really like to try and compete in touring races or other racing, like NASCAR. However, a lot of people I know tell me that I should have been racing when I was 5 instead of doing whatever it was that I was doing. My question is, is it even worth it to try to compete in racing, or should I just shift my focus away to something else?