At the age of 3 I noticed hair - only 1 or 2 - and some breast development (very minimal), however tests were done and they determined she had precocious puberty which was secondary to her CAH.  It was kept under control (puberty completely supressed) by a monthly injection called Depot Lupron.  It worked great.  It stopped puberty and that allowed her to grow more.  Plese check with your dr on this.