Have you thought about precocious puberty?  Are there any other signs besides advanced age?  Just wondering because when my daughter was younger she developed precocious puberty which is sometimes secondary to CAH.  It is treated with monthly injections of lupron.  It immediately stopped any further pubertal development (which was hardly noticeable before) and the bone age stopped the rapid advancement as well. She is now 13 with a bone age of 13 yrs 6 months at last check.  Just a thought.