All newbies are green. After a short time (3 weeks I believe) you will turn prematurely grey. There is nothing you can do about it - not even Grecian 2000 will help.
Its two weeks
It was started about a year/year and a half ago because we kept getting people registering with names that looked like other users and they were causing trouble.
I am really grey, but the grey has been zapped temporarily until the editor or the technos get around to sorting it out, therefore i am temporarily green in a temporary (but very similar ) id until such time as they get it sorted.