New Comer

I'm not sure what the youngest age group is anymore. My suggestion would be that you find a local track and just go visit. Introduce yourselves to any and all and just talk. My experience has been that moto people are some of the best, most trustworthy people you'll ever find. Yep, just go to your local track and ask questions - you will get answers. Hope that helps.

Go to a few local races, you can go to your local bike shop to find info on races in your area. I would recommend off road races as the family atmosphere is a little better. Go to the people with kids around your son's age and talk to them most all are eager to help. The kids race from 5yr's up and there are classes for these ages, most series even have a training wheel class. Good luck and keep us up on your new adventure!