He's more than likely 4 imo. I do think the best way to age is to keep a record and try to document the deer over the years. I've had deer over the years that I've hunted that I knew the minimum age of the deer that I let people look at the tooth wear to age the deer with no other knowledge than just seeing the jaw in their hand. Nearly every time they would estimate age under the minimum age known, which is impossible. I've also had deer that on trail camera that looked like a 3 year old but were older. I had one deer in particular that for 3 years he looked the same age as a 3 year old but was in fact at least 6 by the time he was killed. He never had a huge neck ever, that you typically get with a 4+ year old deer. If I hadn't of lost most of my trailer camera photo data base in a cloud drive crash several years ago, I would be able to post examples.