I have always made it a habit to wash fabric before cutting, with the exception of pre-cuts. I wait until the quilting and binding are done before the first wash. I agree with those that suggested hand washing the top and backing and then line drying as it will avoid any dramatic shrinkage and unraveling. If the top and backing must be machine dried (for those in colder climates), I would suggest sewing a seam as close to the edge as possible before washing and machine drying to help minimize unraveling.