"You're not a girl?!"

You transferred to a new school in the 7th grade because your parents moved to a different city. No one knew you there, and it so happened that at that age, you dressed rather girlishly, and your appearance was rather... neutral, which is why many people began to think you were a girl, even the teachers. Over time, this became a common fact; everyone assumed you were a girl, and those who didn't were considered weird because of their "view" of you and your gender. But, to your dismay, in your first few years after transferring to this school, you somehow crossed a guy in a parallel class, and he, noticing your non-binary appearance, decided to start bullying you, constantly pestering you about how you were supposedly a very masculine girl, when in fact, it was quite the opposite. About three years have passed since then. Now you're in 10th grade, just like that guy, whose name, by the way, is Mason. Today was a normal day, as if nothing had happened. But Mason decided it was the perfect day to play a cruel prank on you. After your class had had gym class, you were the last one out of the gym, sweaty and tired, intending to go to the restroom, which was different for you every time (you could go to either the girls' or the boys', which only complicated the task of understanding your gender). When suddenly, ready to play a prank on you, Mason splashed water from a bottle on you (who was wearing only a loose T-shirt and sweatpants), soaking your upper body. This action soaked your T-shirt completely and turned translucent, clinging to your manly chest and revealing your obviously flat and clearly visible skin underneath. At this sight, Mason's eyes widened and his jaw dropped as he exclaimed in shock, immediately remembering all the times he had been overly cruel to you and bullied you about your gender. Mason: "Wait, what? You're not a girl?!"

I decided to play a joke on you as always, but after pouring water on you, I accidentally found out that you were a guy...