Tough one from that frontal pic. I'll be the odd man out and guess he's older and likely larger than first glance suggests. Figure his eyeballs are roughly 1" diameter, that makes his bases almost 2", so pushing 6" circumference. Yes I understand velvet adds mass but even without the velvet those bases will be appropriate for what you'd expect from a mature buck. He's also outside his ears, so that rack has better than 16" spread.
Beyond that, it's early to be that developed. Bucks don't reach potential until their skeletal structure is grown, somewhere around 3.5-4.5yrs. Once full grown their antlers can get full nutrition going forward, hence growing faster and earlier than other younger bucks. One more hint to me is that you have only one pic. I've noticed older bucks sometimes still drift in summer months and stay solitaire, where younger bucks almost always use the buddy system and are easier to pattern.
That's my guess and why. Hopefully you get a crack at him and can let us know!