I am going to agree... 3.5 yrs maybe 4.5. Still a prtty trim body and "fine" head. Kind of a "tea cup" nose. From the view, he has not begun to develop the pot belly and swayed back (first pic shows a pretty flat back)(as to pot belly one must remember how well fed these deer are) found on a more mature deer. He is just now building mass but, he is still a youngster.
I know it is hard on smaller and more confined pieces of ground but if there was any way, I would like to see him in at least another two years. I suspect with good food and no fighting damage he would be a bruiser.....