Jordan is first described lying on the coach wearing a white, flowing dress. She is almost described as a mannequin.  She is completely extended on her end of the couch, and her chin is slightly raised.  She remains still while he enters the room.

"...completely motionless and with her chin raised a little as if she were balancing something on it which was quite likely to fall. If she saw me out of the corner of her eyes she gave no hint of it"

I think the lifting of the chin shows her as superior to others.  This helps the reader envision her better and helps to get an idea of her personality before she even speaks.