I was always told to sew the sides first and the top and bottom last, which I usually do. But I don't think it really matters. Depending on the fabric used, sometimes looks matter and sometimes size matters. I look at the size. If the width of the fabric, without cutting, would fit one side, then I use it where it fits. I try to make sewing work for me when I can. Quilting is supposed to be fun, not so stressful. Besides no one out there will be marking you with a grade. Do what you please and enjoy!