Who says it has to be square?When you lie under it will you know the difference?If you have it long armed your quilter can even it out a LITTLE.I have to square quilts all the time.And I quilt for some of the best piecers in our area.Your quilt is lovely.Lay it out,lay the borders on it in the middle.If the middle is within an inch of the top and bottom then you can ease that amount in.Make sure you don't ease it in all in 1 spot.Then when it is quilted,the longarmer will lay a large square on each corner and keep it square as she mounts your quilt.You can stay-stitch it along the edges to keep it from stretching anymore.That is a hard pattern but it is lovely.