As of this writing, we're three episodes into Discovery's fourth season. Since Paramount's being oddly coy here, I don't know if that means we have ten more to go, or nine more, or even seven more, or what, but regardless it's still early.
Tilly's clearly on some kind of personal spiritual path here, and one of its strongest instigators has been her focus on what it felt like seeing that first new class of Starfleet Academy graduates in the premiere. As she's said, she looked at those kids and thought of herself just a few years ago, but so much has changed for her. She's really drawn into that whole thing as she searches for something that's the right "wheelhouse" for her moving forward.
What if she decides that what these new generations of graduates need is somebody who's not a whole lot older than them, who can be "hip" and approachable, and has a way with people, to help guide them on their path? What if Tilly comes to the conclusion that having a mom-like, or even big-sister-like, role model around could help? (Possible foreshadowing - Culber pointing out to Tilly that Adira looks up to her.)
All of this to say, what if the potential Starfleet Academy series is set in the 32nd century, and Mary Wiseman is one of its main cast? The writers might be dipping the character's toes in the water this year in preparation for such a possible shift.
I could be 100% off-base here. Do y'all have your own guesses on where Tilly's headed?