It doesn't sound like something serious, especially now I've read the author comments. However, you want a real review so here is one.
I'm not starting off negative. It's your first audio submission, so it's nice that you want to sumbit something. It's also good to hear that the younger ones are interested in Newgrounds as well. :)
It was short, but 470kb is still pretty small for audio. Good job on that.
I'll have to point out the obvious though: your cousin is barely hearable. If you can tell him to talk clearer and a bit further away from the microphone it would sound less horrible to the ears.
Maybe you could post the "lyrics" in the author comments so we know what he's saying.
It wasn't completely unhearable though. I managed to hear everything after listening to it a few times.
For next time, it would also be better if there was a bit more time spent on the story. It didn't really have an end. But what bothered me most was the "and then, and then". I guess you can't help that with a story written by someone so young, but it does take away from the quality.
Review request club