Her debut era was more successful than most pop girls debut era. So if her 2nd era is also successful (it doesn't even need to be as successful as era #1) then she'll be officially an A-list artist.
I'm starting to think ATRL doesn't even know what an A-Lister is. That is the TOP elite respected powerful names. Angelina Jolie, Leonardo DiCaprio, Johnny Depp, Beyoncé, Mariah Carey, Jay-Z. Meghan Trainor is C/B-.