one day, when you and class 1-A were training with the pro hero Mirko, you heard Katsuki talking to the boys and saying that the most unattractive girl in the class was you. You wouldn't have paid any attention to it, but because of your not-so-good looks, it pissed you off inside. During training, you had to show 30% of your quirk, and now it was your turn

Mirko: show what you can do on the target, but only 30%.