Originally Posted by lordofthenerds
They would still know better.
Unless you're saying that XFC made a continuity error (which is completely understandable), and now all mutants are born with their powers at birth.
In the comics its both though. Xaiver even states on film "most powers manifest at puberty" key word... "most" . Charles, Raven, and Kurt in the comics were always told to have been born with there abilities. The movie series obviously gave movie xavier and mystique that same trait