My 6 year old son and I started racing at the end of the summer, 2007. He wanted to try it, so we picked up a used mini for cheap and then he stated that he wanted me to try it too. I'd always wanted to BMX as a kid, but didn't have any opportunity to do so, so I was excited to give it a go. (I happened to have a 2001 Group1 SR20 laying around :))
We started on the weekend the NY and PA districts were having their iron man weekend. something like 8 races in less than 48 hours, including a midnight race and a camp over at one of the tracks. Of course, my son and I raced the two races at our home track and that was it. But, that was enough and now we're addicted and racing every chance we get.
He's really progressed and is making his daddy and mommy proud. I've gotten a little better, but have a long way to go before I can compete with my group (which, so far has stretched from a 10 year old expert to 49 year old novice - both can and do beat me.)
My wife and I are pretty involved with our children and foster children, enrolling them in soccer, t-ball, hockey, gymnastics, and who knows what else. The people that make up the local race scene in our district(s) are the best group of people we've been involved with, yet. Thanks to everyone that makes BMXing with my son so much fun.