It's pretty good for a first serious attempt.
Just a few minor details;
-The way you've done the horn makes it look like it's curved. I can't tell if this is an optical illusion or it actually curving.
-The front left leg seems unnaturally stiff.
-Her left eye needs work. Not sure exactly, but it looks to be a combination of it being the wrong shape as well as the pupil being rather large.
-The tail is good, but there are some bits that could probably be smoothed. But that looks like you probably just forgot them.
-The line of the mouth should probably be one smooth curve instead of having an abrupt turn near the end. As it is, I'm a bit confused as to what her expression is supposed to be.

The only other issues are a matter of personal design preference, so they don't really count.