aww so lucky, I wish I could have experienced their career from the start too!
For me it was no specific era that made me stan them, I just started to randomly listen to kpop songs one day and I noticed many of the songs by that group called twice were really catchy and I kept repeating them.
Then I started to get to know them by watching mainly funny compilation videos on youtube and fell in love
My bias is Momo
wrecker changes almost daily, but its usually Nayeon, Dahyun, Chaeyoung. But I really like Mina too, she is so different from everyone else, but has a lot of really cute and charming sides. Sometimes I just imagine myself building legos with her 
For me it was no specific era that made me stan them, I just started to randomly listen to kpop songs one day and I noticed many of the songs by that group called twice were really catchy and I kept repeating them.
Then I started to get to know them by watching mainly funny compilation videos on youtube and fell in love
My bias is Momo
How about you?