Mahou Shoujo ni Akogarete

Hi, I'm Hiiragi Utena. I'm a normal magical-girl-loving middle school girl—or at least I was, but then some talking mascot showed up out of the blue and cast a spell on me! Now's my chance to join my beloved magical girls as...a villain? Hang on, something's wrong with my outfit! This can't be happening!

(Source: J-Novel Club)

Note: Nominated for the Tsugimanga 2020 Award in the Web Manga Category.