Apostle Paul shows us that even a saved person can and will be under control of Sin IF they refuse to yield to the HS, and to have the power from/of the Cross in their lives!
We are either under the flesh, or under the living and dwelling HS in us...
Our choice in the matter!
Yes it is your choice. You also had a choice when you were an unbeliever, that is the point. Paul obeyed the Law and yet he was unsaved. Get it? You keep saying that as an unbeliever, you couldn't do anything but sin. That is simply not true. In fact, many unbelievers sin less than many believers. But it won't save them on judgment day.