Never heard of anything going by the nose/face. The easiest way to judge the body is by looking at where the neck meets the brisket, the "dip" in the back, and the belly. Beyond that, having the teeth done by a biologist is the only scientific way.
The photo you posted doesn't really show any of those, but going by antler size that deer is either 3.5 or 4.5 years old. Definitely one that someone would be proud of.