Forget the rule ladies (mothers), you can! Although ecru, eggshell or off white are the recommended shades for winter, white denim should not be put in the corner till Spring! "nobody puts white denim in the corner" [my ode to Dirty Dancing].
DO pair the white denim with heavy luscious sweaters, DO wear tall boots with that sweater, and DO mix with shades of cream. DO NOT mix with light cotton blouses and DO NOT pair with open toed shoes.
Pairing white denim with fabrics that are Winter compatible like tweed, wools and angora will shout out to the world, "I know how to wear white after Labor Day and I look good doing it!" [followed by a crossing of the arms and shifting weight to one leg].