No, it is not "A" choice, it is the result of a series of choices. No one make "a" choice to be a drug addict, yet they make all the little choices that lead them right there.
You're right, I was simplifying the whole thing. A good friend of mine put it this way - every minute we come to a "Y" in the road - one choice leads us closer to God's will, one choice away. But the next minute, we can make another choice, one way or another. And no matter how many choices in one direction we've made, we can always choose to go in the other direction any time. But too many choices in the wrong direction make it harder to choose the right direction.