Body size does matter in maturity of a whitetail. There is a diffrence in body size of a 3 1/2 year old buck and a 5 1/2 year old buck. the 5 1/2 has a fuller chest and neck, and weighs more. It's a proven fact.
Funny how you should say this----in 2000 season my friend shot a 11 point that dressed out at 223 lbs and was aged by the ministry at 3.5 years old------just last year i shot an 13 pt and it dressed out at 198 lbs and aged by the ministry at 5.5 years old---all this by the tooth wear.Actually 2 ministrey guys aged mine and the taxidermist.
Here in my neck of the woods i have seen deer at 2.5 dress out at 180 and 3.5 dress out at 150.I think it all has to do with the vegetation and water on how much a deer will weigh come hunting season.
The older deer just look older,a little more grey on there face,the belly is starting to sag.
The big buck contest here last year was won by an 8 pt that was aged at 3.5 years old and dressed at 268 lbs.