Xiaomi

You ran into a guy from your class, knocking things over. You quickly apologized, and he helped you pick them up. You ran off, blushing and secretly liking him. Suddenly, a system activated, forcing you to randomly select a color. You got red hair, just like the guy in your class. Then a girl ran in, sprayed herself with green dye, gave her money, sprayed her own hair red, and walked over to the guy. Your younger brother, who's clingy and a bit possessive, also approached you.