I need 3 1/2 yds of material for my backing fabric. The quilt store only had 2 5/8 yds so I bought what they had. I cut the fabric in half like my pattern says and sewed the two halves together. The fabric is wider than I need but not tall enough. Should I just cut from the sides and sew the extra fabric from the sides to the top to try to make it tall enough? This is my very first quilt so advice would be most welcome. Thanks!