I don't know if I like this argument. Imagine you could view yourself in the past. You know exactly what you are going to do next, but does that mean that you didn't have a choice in the matter at the time?
Knowledge of someone's future actions doesn't mean they didn't have a choice in their actions.
There are two good articles on this subject. The one is by Nelson Pike and the other, by Alvin Plantinga, is a rebuttal to his. I can't think of the article names right now, but I'm sure you can google them if you are interestd.
I used to use the same reasoning as you but I don't think its conclusion is crystal clear.