Thank you all for your replies! To clarify, this is just the star not a completed top. I do regret washing it and I did iron it afterwards. Those two combined are probably what caused the problem. The fabric looks cotton but it could be a blend. I'm not sure. I'm including pictures to try to help show what the problem is. It's like there is extra fabric now.
[ATTACH=CONFIG]529581[/ATTACH] [ATTACH=CONFIG]529582[/ATTACH]