Oh. Well. You are well on you way then. RIP.
Personally I am severely behind on learning all the names of all the newer members. I think more than 10 girl groups debuted in 2018. Groups like Nature, fromis_9, izone, Dream Note, We Girls, Saturday and so on. Meanwhile I still don't know all the members of April, Gugudan and Pristin. Or even older ones like Tahiti and Flashe. There are also groups like Melody Day, Playback, or Purfles that have already disbanded before I even got to learn any of the members. And many others that came and went so fast I can't even remember what they were called. I haven't been watching videos with them like I should. It's the only way to learn them. It's... I, I...