This seems to be a beautifully designed OC. I like pony styles with proportionally smaller heads and longer limbs that goes pretty well with more idealized sorts of character design.
The anatomy isn't perfect though, but if you're interested in being able to draw more convincing horses, there should be a couple of guides I've recently written that may be worth a read even for people who feel they got basics down. They should be under my newest deviations list if you're curious about achieving more perfectionism. One thing I can point out is that the nose can be shaped differently to more convincingly resemble a horse. Horses have much bulkier lower back jaws than what this drawing suggests. It helps to use references to compare your work with.
However, the biggest thing that might be worth trying out is creating solid coloring via filling in the little white spots that are all over the place. You can do this by taking a piece of tissue paper and purposefully smuge the graphite around to have more evenly shaded areas. You will achieve more realistic results that makes it look less like a pencil drawing. Some of the best pencil drawings I've seen can be confused with photographs. Ever wondered if you can one day execute this sort of realism?
Overall, a piece that has a great subject to work with, but the execution is where it kinda falls flat.