I took my son, Justin, to PK when he was about 10-years-old. He will be 21 years-old in June. It has become something we both look forward to doing together. I'm sure that he couldn't relate to many of the issues talked about when he first started going, but he sure can now.
It has been a great time to talk openly about anything and to do fun stuff together. He sees thousands of guys who are growing in the Lord together. My guess is it's something he and his sons would do together when that time comes.
Some kids may not be ready, but many are. Consider it.