It was suggested in another thread that one can choose to be a believer or not.
In the first part of my life, I didn't choose what to believe. If a parent or other adult said something, I believed it.
Later, I began having thoughts that something or other didn't sound correct. This was the birth of skepticism for me. But it was in this stage that I became a Christian, and approached the experience as if it might be what it claimed for itself or not. I was already 18, and had been an apt learner until university life distracted me, and so, had some critical thinking skills. I remember distinctly agreeing with myself to suspend disbelief until I had had a chance to try this religion out and like a pair of shoes, see if it fit or not, or became more comfortable over time. Although I was a believer for many years, I think that it was already too late for me to believe by faith. My belief was based in experience - the euphoria my charismatic first pastor could generate during a church service, which I interpreted as the Holy Spirit.
I say too late for faith, because this all happened in my army years, when I was suffering great angst first at what appeared to be throwing away my dreams of going to medical school (I dropped out of university just ahead of being thrown out) and then at my predicament of being in the army so far from home. I believe that this is what predisposed me to investigate religion - psychological comfort.
But the empiricist in me never died during the period of trying on the religion for fit, despite my efforts at suppressing the cognitive dissonance as part of the suspension of unbelief. I say this, because it was after discharge and a return to my home state that I discovered that the euphoria was not the Holy Spirit, since that feeling didn't follow me to California. That's empiricism.
This was followed by a return to university now older, wiser, and more disciplined, where I learned critical thinking formally, and developed habits of thought that are incompatible with believing by faith. I think that had I remained in that original congregation and in Christianity while attending university, I might have remained a Christian, but I think a social Christian who really didn't believe the theology any longer.
Choosing to believe probably ended at about six or eight years of age for me. Now, I am forced to believe or disbelieve (or remain agnostic) according to experience and the rules for evaluating evidence.