I don't think it's a bad thing having the dice mechanics at the end. Honestly, I'm not sure there's a right place to put it. Too soon and it overwhelms the lore, too late and the mechanics feel disconnected.
It just stood out for being at the very end when there was a bunch of stuff that referenced it earlier in the book.
I wouldn't sweat this too much. Maybe a link to it from an earlier section is all it needs?