Lilly is a fairly disconnected teenager and tries to have it appear as though her isolation is by choice but it's more appropriate to say that she is the victim of the unfortunate circumstances in her life thus far. As she tells us when she is thinking about attending Karyn's birthday party, she had play dates when her mother was alive but after her death, these organized social events stopped and she became her older brothers tag-along. His death, of course, would have left her very much alone if Kyle hadn't haphazardly stumbled back into her life.
Though driven to help her brother, she is reluctant to claim her psychic abilities for fear that they may cause her to be further isolated. Her coming to grips with the reality of her gift is her true coming of age.