It happened over time, through several things, but mainly through realization that the film and music industry is not what I thought it was (mk ultra, occultists, predictive programming).
A year ago I was still listening to Korean and Japanese rock and that's what lead me to this website and this forum - TXT and Red Velvet articles by VC. It only confirmed my suspicion the MVs are full of blasphemy, masonic, luciferian, pedo, etc symbolism. Main thing that convinced me was probably seeing BTS in ritual cloaks and masks at the end of Fake Love, and how much it resembled Kubrick's movie Eyes wide shut. I was already wondering for some time how could someone quite mediocre, and sometimes ridiculous, get so popular and get such a crazy fanbase. Their album sales and YT views were several times higher than sales and views of other k-pop groups together. As I later found out their songs are mainly about selling their souls, boasting about their success or a cry for help.
Since I don't live in US and was a child when 9/11 happened, I was just aware it happened but it didn't change much our everyday life and way of thinking. It was probably first time I've heard term conspiracy theory, and found it fascinating what people were talking about. But I started to question the main narrative only years later. Mainly last year and half. 9/11 happened far away, but muzzles and lockdowns came to this part of the world as well.