If you are as old as I'm thinking you are, then this is great work. It reminds me of when I was that age and used to do things of this sort with tape recorders and my old Macintosh Performa. Keep working on getting more action and fluidity to your animations, because that'll help capture the attention of the viewers more easily. You could even try to incorporate random close up facial expressions at random moments in the animation, to mix it up a bit. Because it gets a bit boring when the characters just sit there motionless for long periods of time, detracting from what could be a much better animation. Additionally, work on getting better sound out of your sound recording. Do some research on this, you might just need a better mic. Anyone who blams this might be just a bit ignorant to the fact that this is a kid pursuing his passion.
If you are as old as I think you are, then you keep on pursuing what you're enjoying, you got a bright future. Overall Good C+