Nice photo.
I would say he is 1 year old(maybe 2).
But my best guess is 1.
I often hear people saying its 2-3-4-5 or something years old, but after stalking roedeers for 30 years i dont think it is so easy as some people think.
Of course you sometimes can say its a typical yearling, but in my opinion you have very good skills if you just can tell if its young, middle aged or old buck.