It baffles me how she felt like she needed to inform you of this and yet doesn't see how transparently immature it is.

you answered your own question Cookie!
Yes she is immature. Emotional development was arrested at the age of 3!
I can't figure out how all these people find new people to hook their claws in so quickly. I am not unattractive and haven't been asked out since he left me seven months ago.
Cookie, how did she get her claws into you? Would you consider a willing participant?