Canon is determined by what the canon sources show, not what a dude who made it says. Besides, he only said she was likely to be ~50 as of K2, so even if you follow the rule that what a person says overrules what is shown, her age is still simply unknown, at best.
"Grant Allen [...] had written a book about the Evolution of the Idea of God. [...] it would be much more interesting if God wrote a book about the evolution of the idea of Grant Allen." ~ G. K. Chesterton, The Everlasting Man