I personally didn't have the opportunity to wrestle as a youngster. I realized when I got to the high school football field the advantage most of these guys had who had spent their younger years on a wrestling mat. Their tenacity, balance and strength for the most part was unmatched by most. My first son started wrestling when he was five. I was encouraged by coaches and other dads to get out on the mat with him so I could learn also. I knew absolutely nothing so I was very hesitant but followed through and haven't looked back. With a lot of help from the men in our club it has been nothing but an exceptional experience. My oldest is 12 now. I also have a 7 year old and 4 year old who saw there older brother doing something they wanted to be involved in. I couldn't say no so they were on the mat before they could wipe by themselves(technically 3 years old). By doing this I knew the responsibility I would have in the practice room. They usually only practiced for the first hour and sometimes they didn't last that long but felt like they were involved. I guess it depends on your club and coaches but I say the sooner the better if there are folks willing to work with kids that age . With the time change and all the technical toys kids have available I'd rather them be rolling around breaking an occasional sweat instead of wearing out their thumbs on the couch! I've talked to many dads who started their kids at 6,7,8 or older and wish they'd have started them when they were 5. So if your going to drop him off and go home, 5 years of age is a great place to start. If you or someone you know is willing to help them ,then a sooner introduction can be advantageous.