I am no expert but I'll tell you what the "experts" taught me while I was obtaining my wildlife management degree. You cannot age a feral hog by its teeth like you can a deer. Tooth wear in hogs is dependent on soil makeup. Since hogs are primarily diggers/rooters, most of their food has soil mixed in with it. Therefore the more sand content the soil contains, the faster the teeth wear. A 5 year old hog down on the Norias division of the King Ranch might show the same wear as a 10 y/o from East Texas.
This is a problem that I have dealt with numerous times with specimens from the archaeological record. While true that different grit amounts and diet can result in different levels of wear, just how much impact that has is not documented (unless it has been done in recent years). Nobody knows what bona fide 5 year old from King Ranch looks like compared to a bona fide 10 year old from east Texas (assuming hogs reach 10 in the wild). This may have been done for a game animals such as deer, but I don't know that it has been done for a pest such as hogs. Add to that things such as oral injuries, chew patterns, and disease and also have an impact. So wear patterns tend to be given in age ranges and as the animal gets older, the ranges tend to get bigger as the accuracy becomes more questionable.
What is most reliable is looking at tooth eruption, but you are well beyond this (obviously), so it comes down to tooth wear. The problem I am having with trying to assess tooth age is that I cannot clearly see the wear on the last tooth (M3) on each side. Confusing the matter more is that you have differential wear on each side. The Right M1 and M2 show more wear than the Left M1 and M2 and the Left M3 shows more wear than the Right M3. So you have a bit of a wonky chew pattern that declarifies things a bit. From what I can see, your hog is at
least in the 3.5-4.5 year old age category.
Can you provide a better picture of the M3s? Your closeup of them actually had the table surface in focus and not the surface of the teeth.