how did you first hear about/learn about/become fans of K-pop groups like this?
I've been aware of kpop since SES but never really paid attention to it. A few years ago I made some Korean friends and my best friend went to Korea for 2 years, so through talking to them and watching Korean movies with my Korean friends I guess my general interest increased.
Early last year, someone on GAF posted a pic of Hyuna and I thought she was cute so I checked out who it was. At the time there was some controversy around her because of Change, so I was immediately greeted with the drama of kpop culture. That was interesting in itself, but then when I checked youtube to find out what the deal with the video was I learned about both the nature of their music programs (awesome) and Invincible Youth, which quickly led me into the rest.
And how did your fandom develop to the level it is now?
Quite naturally? Before this happened, I had accumulated over 500 albums on Zune from all music types and many different countries around the world in the span of a year. I don't watch TV, rarely watch movies or read books, and have been significantly cutting down on videogames. Music is my hobby, so I had quite a capacity to jump right in and thoroughly explore an entire new industry.
On top of that, kpop is much more personable than western media, so it got me to actually watch some shows and movies again. Now that I've started learning the language and made a few dozen more Korean friends, it's just helpful for my continuing personal study and social life.