Kostornaia will be 17 this month, she is a year older than Shcherbakova and Trusova.In addition to my previous thoughts, I hope Kostornaia says nothing.
However, let's get real, Kostornaia is already 16. Since Kostornaia is apparently very bright, she probably already saw a pattern and made a reasonable prediction about where she would be by 2022 if she stayed.
Maybe Shcherbakova, also being 16, will be in a better place since she has something that resembles a 4Lz, although picking with a full blade could cause the technical panel to call it a Loop jump or unlisted jump.
However, my guess is that the 14 year olds with quads in Eteri's group will be her favorites by 2022, like Zagitova was by 2018.