In my opinion it depends on their weight. If they are at a smaller weight you may find that the bracket has several 6 and unders that have moved up. I would be cautious if your son is at higher weight because you could be looking at kids in 8 and under that could actually be 9 wrestling your 6 year old.

Leave it up to your kid to make the final decision though - they have a lot of years ahead of them!