When I look at verses 13 through 16, I read of the quality of delight. God continues to take pleasure in his creation, and that includes his beloved human beings:
You formed my inmost being;
you knit me in my mother’s womb.
I praise you, because I am wonderfully made;
wonderful are your works!
My very self you know.
My bones are not hidden from you,
When I was being made in secret,
fashioned in the depths of the earth.
Your eyes saw me unformed;
in your book all are written down;
my days were shaped, before one came to be.
This brings to mind the oft-asked question: If God knows and sees all of time, do we have free will? What does it mean that God pursues us, even with the knowledge that we might ultimately fail? Does it mean God continues to love us, wish the best for us, even though we are inevitably sinners?
Catholic Sensibility 
Delight [Delighting (חָפֵץ, chaphets in Hebrew)] is my strongest frequency in contemplation.
The above selection from Psalm 139 reminds me of this selection from Proverbs 8:
[22] The LORD created me at the beginning of his work,
the first of his acts of old.
[23] Ages ago I was set up,
at the first, before the beginning of the earth.
[24] When there were no depths I was brought forth,
when there were no springs abounding with water.
[25] Before the mountains had been shaped,
before the hills, I was brought forth;
[26] before he had made the earth with its fields,
or the first of the dust of the world.
[27] When he established the heavens, I was there,
when he drew a circle on the face of the deep,
[28] when he made firm the skies above,
when he established the fountains of the deep,
[29] when he assigned to the sea its limit,
so that the waters might not transgress his command,
when he marked out the foundations of the earth,
[30] then I was beside him, like a master workman;
and I was daily his delight,
rejoicing before him always,
[31] rejoicing in his inhabited world
and delighting in the sons of men.
Note: That’s the RSV translation.
As for your question, the Catholic approach is to differentiate what God *necessarily* wills. And that foreknowledge includes knowledge of our free choice. So we don’t get into the double predestination thicket.
One part of the equation, Thomistically:
http://www.newadvent.org/summa/1019.htm#article3