I always starch the fabric I'm going to use that might have any bias edges. I make it stiff and then it's easier not to stretch the pieces. Yours doesn't look as bad as some of my early ones! LOL! Use a puffy batting & you'll be amazed how it pulls it in when you do your free motion quilting on it. You've done a very nice job on it so far! It's a nice looking quilt top!!