Three weeks before your rut, tarsal staining, buffalo hump, neck almost goes seamlessly into his chest, and his legs appear short. But, he doesnt have a bell or a sway back. I will guess 5 1/2. Especially if you are located on the western edge of the state. I hunted the Logansport area of central Indiana for a few seasons and never saw a buck like that!
BTW, I learned all those cliches from the Age This! column of Quality Whitetails. If I end up quitting QDMA, I will miss that section. There are plenty of age guessing games on the forums, but I liked to use the detailed explanations in QW as a monthly refresher.
Also, not that it really matters, but there is an aging subcategory on this forum under the Trail Camera major heading.