I'm new at quilting, and am making a quilt for my new grand-daughter to be...I've finished the top and it measures 38 1/4 X 44 1/4 exactly. Per instructions, my backing needs to be cut at least 3" larger than the quilt on all sides... My backing piece (what's left of it) only measures 41" x 51 1/4". Obviously, although the backing is bigger, it doesn't equate to 3" inches on the 2 sides of the quilt. I'm assuming that the 3" requirement has to do with the quilting - meaning maybe it draws up during the quilting process? I don't want to have to go buy more material for this small amount.....how crucial is it? Thanks for any advice...