At what point would you move from the old stuff to the new stuff to keep someone from being too confused?
I don’t think confusion is a big concern - if she has some basic familiarity with the franchise, it shouldn’t take much more than explaining when the series is set. Beyond that, each show should stand on its own.
The only possible exception to this is “Picard,” which is the most reliant on a previous series, but even then, the show should give the viewer enough information to watch it on its own terms.