This is very good for a first horse. I like it, but I love horses too. Especially dark colored ones. This one looks a little "devilish" LOL
My monitor is too dark to give a complete critique, but I'll go with what I can see for now. I can say the eyes versus the cheeks and the muzzle are incorrect. Horses have eyes set on the sides so that if it is facing you, directly like yours is, the cheeks go flat down and are almost not visible. If turned a little like yours seems to be, one side cheek would completely disappear.. (Except in big stallions with puffy hormonal cheeks). This one's eyes are also too far down from it's ears Also, you've tapered the muzzle to far inward and pointed, it needs less steep of an angle inward. Here's a photo of a horse looking at you. See how the eyes are set and the cheek is hardly visible.. the bone bump under the eye is where the muzzle tapers inward some, but if you notice, it isn't as steeply inward as yours and it tapers slightly back outward at the base for the nostril flare:

The eyes look very canine and I know you mentioned you usually draw canine so I agree with the other comment, you may want to check out anatomy and eyes a bit more or tutorials. It's incorrectly shaped for facing you. Try making the eye socket and then if the horse is facing you, all you'll see is almost a half moon shape inside the socket because the eyeball faces forward and part of it is obscured by the skull. (I hope I described that ok, I can picture it but it's hard to describe.) This little horse does somewhat have the appearance of a wolfs head on a horses body. The ears are too wide at the base, horses have ears that swivel more than canines or at least they appear to but are narrower, taller or longer, and more tubular in shape than canines. I think the chest is missing a muscle set similar to a human pectorals, but again my monitor isn't the best. The last thing I noticed was the legs. You've made the legs humanized meaning the musculature is highlighted incorrectly causing it's stifle, thigh, quarter muscle and gaskin area to look like our own human thighs (On rear legs. I didn't remember to check the front legs.). Feel free to look in my gallery if you want, there's some pretty good horses in there.
Again, my monitor is dark, so I will look at the library within a couple of days and see if I can find any other items to assist with.
Hope this is helpful.
I will pm you with more tips after I've had a chance to use a better computer to look at it.
Equid