That is a very pretty quilt. I like the pattern. I made the same mistake on my first large quilt, and a friend took it all out and showed me how to do it correctly, by measuring the middle and then quartering the quilt edge and border pinning at the quaters and then basting to get it just right. Triangles on the edges of the quilt can really stretch. Another thing she taught me was to press with spray startch easing in the excess strech before attaching the border. My quilt turned out great.