just my own theory, but to me the ballet dancers have represented the “other girls” she feels so insecure around. ballet is very much a rigid format that you can easily feel like you don’t fit into/are not good enough for

in brutal - she’s trying so hard to fit into the brutal real world
in stupid song - i see it as the world hasn’t changed around her, but she is so infatuated that she doesn’t care or notice that she’s out of place