The Life of Captain Marvel #3 effectively establishes that Carol's run-in with Mar-Vell and the Psyche-Magnitron was not her first time encountering the Kree. This is a major departure from the hero's original origin story, which saw her effectively stumble into her powers as a well-meaning citizen just trying to do some good in a weird, alien situation. The new issue may hint that Carol was always predisposed to become a hero, and that her Kree-human hybridization might not be the result of the Psyche-Magnitron at all, but rather a matter of simple genetics -- if we are assume that her mother is, in fact, Kree and her father was human. Now that's a comic book coincidence if there ever was one.
The revelation also has the added effect of fleshing out Marie's character even more. Up until this point, Marie Danvers has been portrayed as a woman who was cheated on years ago and simply doesn't want to address it, much like she doesn't want to address the fact that her husband was an abusive jerk. The reveal that she is a Kree fighter (we have to assume she's a fighter, as she claims she can take care of the Kree clone, who doesn't seem receptive to the diplomatic approach) adds a layer of complexity to the character, putting her on the same power level (or greater) as Carol, but casting her in the tragic light of someone who knows a relationship is bad but won't leave. "I thought could save him," Marie says. For a Kree warrior, she's certainly swamped in a very human, and relatable, drama.
There are some mysteries that remain, though. The issue also reveals that Carol seemingly witnessed her father being unfaithful to her mother. In a flashback, we see Joseph Danvers snogging a floating woman that Carol determines "definitely wasn't from around here." The Life of Captain Marvel has so far hinted heavily that Joseph Danvers' fling was with an alien woman, whose identity is yet to be revealed. The reveal that Marie Danvers is really a Kree lends some credence to the theory that she was actually that other woman but dealing with the perils of a dual identity. It would certainly be very strange for a jerkwad like Joseph Danvers to have attracted the affections of not one, but two alien women (lest he is later revealed to be Star Trek's Captain James T. Kirk in disguise). It's all sticky and complicated, and we won't know more for certain until The Life of Captain Marvel #4. Regardless, the Kree clone who has been tearing Harpswell apart certainly has it out for Marie Danvers.
There is a certain amount of irony in the fact that Captain Marvel's origin story has been so spectacularly rewritten now, when the hero's cultural cache is nearing its zenith. The first teaser for the Marvel Cinematic Universe's Captain Marvel released just the other day and is poised to delve into its own take on Carol's backstory. On top of that, many fans are clamoring to see Brie Larson's version of the hero take Thanos down a peg when Avengers 4 hits theaters, especially after the heartbreaking end of Avengers: Infinity War. It's unclear if Captain Marvel or Avengers 4 will take Carol's rejuvenated story into account, but it doesn't really matter. The biggest Captain Marvel story is happening in comics right now, and we're eager to see how it plays out.