Yes, the flannel needs to be washed, probably twice, in hot water and dried in the dryer to get rid of the shrinkage. Some flannel shrinks up to a couple of inches per yard. Starching will not help with that. I would recommend that you tape (or use clips) the backing to a table. Be sure that you do not stretch the backing- just keep it snug. Lay on the batting and then the top. Baste with pins placed 4-5 inches apart or hand baste. Then, SDID if you want to quilt each block. Reduce the pressure on the quilting foot. A high loft batting looks really nice but the preparation is very important. Quilt from the center and be prepared to adjust basting as you move outward. It is doable so don't be discouraged.