Copper, This look great and you have learned a lot since you started. The only thing id have to say about it, is that the horse isnt fully cut out, I can still see the original background. So maybe draw an outline to cover or draw in some ears.
And the horse doesn't really pop out so much. Its a beautiful picture, but I feel like it may need a bit of a 'POP'
and since you have a tablet you can totally use it to make the shadows and highlights pop out.