“sober certainty of waking bliss”

So my presentation on typology has me thinking all about time and the relationships between all the characters, etc. and all the work I’ve done on it today reminded me of something I”ve had a problem with since Book 3, but never bothered to ask about. So the Son offers to take the fall for mankind in Book 3…man doesn’t fall until Book 9? How does this compute? Am I totally missing something? God knows man will fall all the way back in Book 3?! (I mean, he actually knows about the fall and redemption in the first few lines of the epic, as I will talk about in my presentation, but seriously, they actually talk about it in Book 3). I just have trouble reconciling the timeline here, of the books. Do they occur in chronological order? Or since time before the fall is eternal does it really not matter when the Son decided to take the punishment to redeem mankind? If they decided way back when, why did God wait so long to send his son to earth? Anyway, I know everyone is busy with their papers (me too, I should be writing right now) but this question has been on my mind for awhile.