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: it happened today when i was 15 or so. by then, the last time i had ever kissed or dated a girl was when i was 6. i was pretty much outside the social circle in high school: nobody particularly liked or hated me as i was rather unpopular and unknown, so my perceived chances of ever scoring a girlfriend there were pretty low.

that day there was going to be a popular music festival, and me and some other guys from my class were going together. muse would be headlining that day, and since at the time i was somewhat into them, i wore my muse t-shirt from a previous concert that day to school.

i was casually walking by the school when a girl from the previous grade called out to me and said: "hey, great shirt! will you give it to me?". i smiled awkwardly, said some words and kept on walking. she was actually good looking despite me never having really noticed her.

i stumbled upon said girl several other times that day, but now with some guys from my class walking with me. she kept greeting me and asking for my t-shirt every single time, and i would smile, mumble a few words and keep on walking. when my friends noticed, they said "whoa man, that girl's into you! go talk to her!". i brushed that aside and said that she was just teasing me because she liked my shirt and because she was probably going to the concert as well. they would actually sound a bit 'pissed' sometimes when telling me that, probably dumbfounded by my negativity. in my mind there was no way that girl was trying to flirt with me.

i stumbled upon her on the concert, and same thing happened. even for several days after the concert she would say to me "hey, still waiting for that shirt!". eventually she stopped talking to me and i forgot all of that. this was almost 7 years ago; for some reason i recalled that event today and i realized how incredibly naive i was. i had a pretty low self-esteem towards my interactions with girls at the time, so i was probably protecting myself by brushing aside that situation as it just being a girl teasing me because she liked my shirt. and there went my chance of ever scoring in high school. sorry for the long text, i tend to write too much details.

TIFU by being oblivious towards a girl flirting