It's a fine start for sure. Perhaps tapering the hill a bit more, so that the face of the hill isn't so steep. Perhaps adding some long grass, or a few different flocks for the grass, to give you a more varied look.
Other than that, you are on your way.
Dude, that is like sooooo yesterday ;-) no seriously, i like basic and old school stuff, this should be great for playing, but next time try to do something more spectacular (additionally, this looks very sterile; I know it's GW style but nevertheless) I know this is your first work but set yourself higher goals and it will surely work out fine!