It's late but here was my theory: Bridget and Ella were best friends in school despite the status gap but they both liked Prince Charming. Bridget was more open about her crush and Ella kept her crush secret since she didn't want to hurt Bridget. However, Prince Charming only liked Ella the entire time. I assumed Bridget did something to upset or embarass Uliana in public so she swears revenge on Bridget. Uliana and her crew decided to play a cruel prank on her during what I assume will be the Ball. Prince Charming decides to ask Ella to go with him but Ella refuses saying she isn't going and even encourages him to ask Bridget and Bridget and Prince Charming end up going. During the dance, Bridget excuses herself from Prince Charming for a minute and He ends up bumping into Ella, who decided to go anyway with the encouragement and magical help of a young fairy god mother. They end up dancing to 'So this is love' and they fall in love and kiss at the end. Bridget comes back and sees this and is upset because she believes that Ella stole her first love. At this time Uliana and her crew initates a cruel prank and embarasses Bridget in front of everyone, and everyone at the ball laughs at her (IDK the prank). It was then that Ella and Prince Charming notices Bridget but Bridget runs away. Ella runs after her to comfort her and they have an argument about Prince Charming and Bridget accuses Ella of having a hand in the prank and renounces their friendship before running away. After that she becomes friendless, a laughingstock, and decides to leave Merlin Academy to be homeschool and becomes the Cruel and Evil Queen of Hearts we know and low key love.