Everyone goes under the same rules sooner or later your son will be on the top of the age group and no longer on the bottom. Tell your son that your day is coming that you will be the oldest and with your experience you will dominate the mat again. My son is four and he is in preschool and even though he only made it to districts and not state we figure that he still has 3 total years in the 6 and under bracket and 5 total years with the 8 and under he will have a definite advantage by the time he is 6 or 8 for state. It doesn't matter when the cut off date is someone has to be the youngest and someone will complain about there son is the youngest so why complain just incourage your son to do his best. We tell my son it doesn't matter if you win or lose as long and he does his best that is all that matters. Just encourage your son and everything will work out.