There is a differenent between fore-knowledge(?) and pre-determination. As you say , God knows who will accept and who won't but I don't believe he says "hmm, I think I'll keep this one, no not this one etc.
I think that He chooses those who turn out the way He wants. (Of course He knows how everyone will turn out).
It's a fairly complex issue (like the nature of God) ... I don't pretend to completely understand it.
I, ultimately, trust and rely upon the goodness & love of God.