From what I have learned, 8 may not be considered precocious puberty.  It may be the bottom end of the "normal" range for a girl to start puberty now.  It depends on lots of things - race and what part of the world you live in are part of that.  Having said that, my daughter is also SWCAH and she was diagnosed with precocious puberty at the ago of 5 and put on monthly injections of Lupron until she was 13 in order to slow down the rapid advancement of her bone age.  They should be doing bone age tests on your daughter.  I would insist that she be checked for CPP and find out what her bone age is.  CPP can be a secondary condition brought on by CAH.  Good luck.