She's always been considered the first X-Men. You age her, and you age the franchise considerably. I think that's why they've been aging her and reducing her age and everything.
I think you may be underestimating the importance of Giant-Size and the fateful year of 1975.
Jean is the age of the 1963 team. Ororo is the age of the 1975 team. It's Ororo who must never age.
Colossus and Nightcrawler are also the age of the 1975 team. They can't age either.
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