Abandoned seems to fit what Nene feels. She nearly starved to death in some apartment when her owner disappeared, she's only been sentient for a year, and she learned her past in a dream the day of this chapter.
In order to be a Nekomata, a cat has to be unusually long-lived, so her age was intentional
What about that panel where mahoro says she's a place Nene can come back to, though? Now that's what this chapter is all about