Your right about it being short, but more to the point, in the future try to have your movies explain something or be funny or tell the viewer a story. In other words try to convey a point that you set out to make the video for in the first place.
Setting aside the lack of concept, this isn't a bad animation, I've seen a lot worse, and this being your first I can see you have potential, if you develop your skills you could get really good.
But for now, keep practicing.