Finish it how you started it. A lot of the time the stitching length is controlled by how fast your moving the material under the needle. Are you using a walking foot? Next time you start a project to quilt, make yourself a sample sandwich, and check all those things out. I always do this, I make a 9x9 sandwich, and quilt this to practice and check everything out, then I have a nice potholder, I save them up and give them as christmas gifts. Check out daystyledesigns.com she has a lot of info on her site.