I think I'm missing something here, and might have forgotten or not read something properly, is the married woman at the end her friend with the cat-ear like hair?
Nah that's not Takahashi. Without going back through all the chapters to see if she appeared before, i'd wager the married lady is simply one of her readers whom she met before at an event like this, that's why she greets her like that.
Ah okay, thanks. I was...very worried there for a second haha
Yeah I tried to skim through previous chapter but couldn't find her, so I was just like "hmm..."
In the new chapter (17 not 18, oops), Takahashi mentions the parent teacher conferences and we see the exact same image of a classroom. Chapter 1 used the image as a cutaway, and it wasn't explicitly connected to the high school storyline, it just happened before the Christmas date(?). So "ever since that day we still couldn't be normal" is as much about the confession event as any high school stuff.
Oh, so that's what "normal" meant all along! The author was playing the long game, I see.
EDIT: "Normal" basically referred to "being an inextricable part of each other's normal life". "Still not normal" meant that the two of them were still hesitant to treat each other as essential parts of their lives. Only a prolonged absence made them consciously want to normalize their permanent togetherness.