It's a good start. For the legs. get some thinner paper, lay it over what you've done, and keep drawing sets of legs 'til you've got a set that look right - THEN add them in on the real thing. Nice expression on the horse's face, too. The neck could be a bit thicker, not much, but it's a teeny bit thin to be holding up that head.

Of course your mom will like it - YOU made it!