I think perhaps that a different colored background would offer a bit more interest to this shot, but you've done a good job of capturing the detail on the dog.
a very sweet face -- such a great model. I get the connection between the two of you for sure. On the technical side -- there seem to be some red dots on your white background that could have been dodged out. Also the oof right eye distracts me a bit. I like the black and white choice as it highlights your title in the tones on the "gray" muzzle. In all, one of my higher scorers.
I find this photo to be a bit oversharpened and unnatural looking. The reflection in the dogs eyes makes it look possessed. Having said that, I will say that you have done a good job illustrating a dog aging.