If I'm not mistaken, that should put her into about the right age-bracket for that particular additive.
I know that I've seen at least one extreme case of a tan doll starting to turn funny colors.... but, even on that doll, it was pretty obvious that she'd been stationary in a strong light situation for an extended period of time. Then again, the person who had the doll, also owned another that was nearly banana yellow. ^.~
<3
-Kiki-chan78