Bit of a 'tweener between 2 1/2 and 3 1/2. The front cusp of the 4th tooth displays little wear, but the back cusp does show wear. In addition, the 3rd tooth (youngest in the mouth) shows excessive wear for a 2 1/2 year-old. The last cusp of the 6th tooth also shows heavy wear.
Again, although this deer is a good example of a "tweener," I would go with the preponderance of the evidence and say 3 1/2.