Nice looking deer and with that one nice side view you can see he has a nice defined brisket where deer 2 1/2 wont have ! basically with his head up a younger deer neck would run straight down its leg with out the nice brisket hanging out in front of the leg! this tells me hes older than 2 years old as far as his back gos it is about right for any deer up to to 5 or 6 but the one thing that tells me he is not 4 1/2 is the size of his front shoulders! a 4 year old will have front shoulders nearly as large as there hind shoulders! not as big more evenly balanced with each other!
you made the right call in m opinion he is a 3 1/2 year old!
good hunting!