Cool fabric for a OBW, never would've thought of using that but it looks cool.
As for the borders, I think you need to take them off and re-cut them. They look too long for the center. Measure your center across top, mid & bottom and take the average. Then make your border that length. Do this for top & bottom first, then measure again for sides. You have to do this for each border that you add.
It sounds like a lot of undoing and redoing but from the pix it looks pretty wavy and I'm not sure you'll quilt it out. You may end up with an unsquare quilt (or large dogs ears). I think the center is worth the re-do, you'll be happier in the end.
Good luck and hope you don't mind the advice.