Well, yum. That's definitely not bad for a beginner (semi-beginner anyway, you still have lots of room to learn). I especially like the way the grass overlaps the stock.
i feel that the wallpaper is much too empty, however... Perhaps adding some text wouldn't hurt? A sun too, giving the rest of the wallpaper a light source, if possible.
I should have helped you with that before you submitted it though. Oh well.
All in all, really nice, and the best thing I've seen from you yet. There are still some things you could do to improve it, though.