Impressive for a first animation
Graphics - 7/10 - I felt the characters and backgrounds were quite nicely drawn with a sort of "coolness" to the colour scheme, which suited the animation nicely. My biggest gripe with the graphical side of things was that when things were moving, it looked a little choppy. That could probably be ironed out with practice, so good job overall.
Content - 7/10 - It's always a sign of good storytelling (be it simple or complex) when the viewer understands exactly what is going on without a word of dialogue spoken. Great work here, however one small problem is that the animation loops itself without playing the music, so you might want to add a stop command on the final frame.
Sound - 7/10 - Already mentioned there not being dialogue, however in this case it wasn't really needed. The music was appropriate, not much else to say.
Overall - 7/10 - For a first attempt at an animation this was most impressive. You definitely deserve a good grade for this :P Good luck with improving your animations skills, and I hope to see more work from you in the future.