Not saying this buck couldn't be 3 1/2, just that based on what little we have to go by, am only reasonably sure he's at least 2 1/2.
All any of us are doing here is giving our best guess, and those guesses can be pretty wild on summertime velvet bucks. Generally, antler size is a poor indictor of age, but antler mass has a lot of correlation to age (at least more than width or tallness). So while I'm downplaying using antlers for aging, with those particular two pics, there isn't a lot more to evaluate. Assuming he's in velvet in that top daytime pic, his mass is more in line with a 1 1/2-yr-old buck than a 3 1/2 (just considering the averages). That has been part of why I said 2 1/2 or older. Show some more pics, including a nice full side view, and that might change to 3 1/2 or older.