Why's this have one star? Sure it's not the best, but it's certainly not the worst - doubly so considering this is your first Garageband song. I think it's a little easy to hear you experimenting in GB, y'know? Like how you have the piano do its thing, then the flute repeats it, then you put them together at the same time... Doesn't really sound bad, just sounds like you're playing around, figuring it out. That's what it sounded like to me anyway, I could be totally wrong lol.
I vote you keep it up, you can only get better! :)