Well, I can't see a thing wrong with it. From your button comment, I'm guessing that the center seams don't meet your expectations, but with your color choices, it's not obvious! Had you chosen fabrics for the star with a much higher contrast there may have been an issue, really it's just fine!
As far as FMQ, here's a great place to start:
http://freemotionquilting.blogspot.c...tart-here.html