Certified GKH Gardening Expert
Jade flowering in the home is rare. Growing conditions, such as light and water, determine whether your jade will produce flowers in winter. To encourage December blooming, provide natural lighting during the day and keep the plant in complete darkness for 12 hours, beginning in mid-October. Water sparingly until buds have formed and then resume normal watering.
Also I think light is a critical factor. All the jades I've seen flowering were grown outside.