Looks like a bit of overkill, but I assume you've looked at the time you have and set yourself at a fair maximum, which is a very good idea. If you find that you have more-than-enough understanding of the text, you can stop there, knowing that you can instantly get it back with your mind-map.
Since you're just starting out, let me give you some stock advice - mind-map. I remember once after PhotoReading the Mindmap Book, and of course going through the PhotoReading Whole Mind System, I looked at the inside front cover of the Book of the Subgenius. It's about a 200 page book, lots of artwork, but A-4 sized paper. I was STUNNED. There was a mindmap in there, and it contained the ENTIRE book. A 200 page book, reduced down to a single page of obscure and arcane images. It would mean nothing to someone who hadn't read the book, and would be "interesting" to most people who had, but to a mind-mapper, it was the entire book.
Naturally, the ability to condence a book down to a page or two is very good for pre-test studying, and even better for cheat-sheets.