A very long time ago (around 2011?) I used to watch a lot of MMD videos and characters from Touhou would show up a lot in them, I really liked their designs but didn't know where they were from at the time.
A couple years later I find U.N. Owen was her? on YT and recognized Flandre, then looked up Touhou and got super into it
Until last year, I've only ever listened to the music, play fangames, draw the characters, etc. (then I got Hidden Star in Four Seasons as my first official Touhou game and I've only gotten more into the series)