I've let allot of 3.5 year old bucks walk. Most were in that 120" range and some were 130 inchers. How do I know they were 3.5, I've watched them from there 1st rack on. Allot of hunters call 3.5 mature, nothing wrong with that! In my woods I call a 4.5 a mature deer. If a person wants to get scientific about it, a 1.5 year old is mature too then. He can breed just like the big boys!