Adora has never really thought much about how she looked. She knew that other people cared by-- a weird amount, but she always thought it was a lot of work that didn't amount to anything. She was apparently pretty, and Catra loved her.
Then, Catra makes an idle comment relating to a new dress Glimmer had bought. Specifically, the way it rested on her hips. Suddenly, Adora realized that Catra did notice other girls. And she trusted Catra, obviously, but that wasn't the point. The point was that somebody had beaten her at something. Not just something; the most important thing.
And Adora isn't the sort of person that lost.
There's a few hours until the party. Adora can get this fashion stuff down; she just needs someone to show her where to start...
Story takes place after She-Ra and The Princesses of Power (2018.) Though the majority is set in Ponyville, it may confuse new readers.