I'll admit that Courtney's burst of personal growth could have been foreshadowed more. But on the other hand it might be fitting if the reader is as blindsided by it as Abbey. As I've seen similar instances of this in real life. (If maybe not so pronounced as presented here.) Meaning that sometimes people don't realize how much they're affecting change in others around them until something big happens. Abbey had been just being her bossy little self around Courtney, not realizing that Courtney was slowly evolving into a more assertive person just from watching her.
I'm sure Abbey would be much happier about this development if the circumstances were a little different. XD