Were all my days written before?

I decided to title this blog as Psalm 139 - NVI due to verse 16:

Your eyes saw my unformed body;
    all the days ordained for me were written in your book
    before one of them came to be.

When I read it, I understood that all my days were written in the book of the Lord. A friend of mine explained that "days" are not in Hebrew. In King James, we see "members" instead of "days" which is closer to the original in Hebrew, although "members" are not written too.

16 Thine eyes did see my substance, yet being unperfect; and in thy book all my members were written, which in continuance were fashioned, when as yet there was none of them.

My friend understood that this divine book is the DNA code which encodes how the members and the whole body will be created. He believes in Free Will so he advocates that the Lord has not written all our days in a book. If a man sins because his will is totally separated from the Lord's will, how would the Lord has written all our days?
Well, now I am somehow convinced that the King James translation is better than NVI, but I still believe that the Lord knows every detail of my future, my decisions and my sins included, that is, the meaning of NVI translation is also correct.
The Lord is outside this finite universe, this finite space and time; and for me, He knows everything, every quantum particle, every electron location of this universe. He knows all my thoughts, all my sins and all my future sins because as a writer outside his own book, He may see things in which time He desires.
He even designed me before creates the Universe, as in Ephesians 1. How? I do not know. Why? He wanted me to have some grasp of  who He is and in doing so, adore Him.