I would say 4.5 to be mature. My brother got an 8 point that was aged by teeth at 6.5 years. Huge, 208 field dressed. Had a broadhead embedded in shoulder that was healed over. Had a shotgun slug wound entry and exit healed over. One lucky buck. Also had rifle holes, .22 I think, in its ear and front leg. I think someone tried to poach it at night with a rifle. He got it one shot with 12 gauge slug. Massive horns scored around 135. Some are under the opinion that he was on his way down as far as rack, past his prime ya know.