Young irns have paler beaks.
http://home.online.nl/psittaculaworld/S ... rameri.htm
At that age a pale beak is fairly normal, I can't find any references to what age it really starts to brighten up... I'm sure mine did at around 6 months old or so. I was worried about our second bird because it seemed to take an eternity for her beak to get bright. I thought her diet must be lacking something.
Diet, health etc can effect beak color too. Again anecdotal, a friend of mine switched around the diet of her mature birds and their beaks became a more vibrant red over the course of a couple months or so.