Definition: In this task, you are given a Reddit post as a text. Your task is to generate a title for this text. The title should start with "TIFU by", followed by a situation that caused humor. The title should contain 7-12 words, ideally.
Input: Text: so the other day in school the teacher was reading off the attendance and repeatedly asked if anyone had seen "john" (fake name). everyone said no and i then asked, rather loudly, "who the hell is that?" now i had noticed from the past few days that john had the same last name as a kid who left last year, and looked slightly similar, but they had different first names, so i assumed it was just a coincidence. also, the high school i'm at has practically no new kids join each year, so he had to have been here last year. anyway, after my outburst that wasn't intended for the whole class to hear, another kid pulled me aside and whispered "that was sarah from last year. she's transgender." 
ultra liberal teacher + students were pissed that i hadn't known, and proceeded to scowl at me for the rest of the day

TIFU by being oblivious to a gender change