I am no pro or biologist, but judging by the gut hanging below the ribcage I would say definitely mature. Great antler mass, good symmetry. Long nose. 4 1/2 +. I might even venture to say 5 1/2 or older. But I don't know all the other factors that influence those very traits or characteristics. That would be the age of a deer like that in my neck of the woods. One thing I have noticed over the years is that much like men when we hit that certain maturity, we tend to start to get a gut, unless we work hard to keep it flat. Whereas when we are in our teens and into our early adulthood, through our twenties, a flat stomach is natural. Of course this is just my opinion and I may be way off.
It is not about the equipment you have to use,
It is about how you use the equipment you have. :D