Does it really matter? If a 2 1/2 or 3 1/2 year old deer is mature to you, then take him. I believe what some of the hunters are meaning when they say in my area a 3 1/2 yr. old is mature, is if they don't take that deer, they will probably never see him again. Most hunters don't have enough land, if any, to grow and manage trophy bucks. A 3 1/2 yr. old buck is a mature enough deer to take for most hunters. I'll take a nice 2 1/2 yr. old if given the chance. I own land, but not enough to be confident that a 2 1/2 or 3 1/2 yr. oldbuck will remain there. They are going to travel and I guarantee most will be shot by another hunter. It might as well be me taking that nice 2 or 3 1/2 year old buck rather than someone else. Now I'm not saying I will take every 2 1/2 yr. old buck that walks by, but if he has a nice rack, then I probably will. I supposeif you are a trophy guru, then a 3 1/2 yr. old buck is not mature enough for you, and that's perfectly fine,but for most of us hunters, a 3 1/2 yr. old will do just fine. Is a 3 1/2 yr. old buck mature to me? I'll just say if he walks by me, there's a real good chance he won't make it to 4 1/2.