However, this can change throughout our lives & is never static. We are prime examples of this in that we did not always hold the same position on religion as we do now & this is partially because we have received new input which questioned the validity of what we once believed to be unquestionable.
Oh, yes, absolutely! I hope I didn't give the impression that I think we can't break out of the influences that shape our beliefs.
But again that is not simply by "choosing" not to believe - but as a result of - as you say - learning new knowledge, or having the strength and courage to analyse our beliefs rationally etc... In other words our beliefs change because of new information, new perspectives, changes to our environment that make this possible and so on.
Not simply "choosing to believe something else".
My point is that one can't simply choose what to believe.
Belief comes about through many factors - yes, because of thought, rational analysis but also cultural, environmental and so on.
To say we can't simply "choose" what to believe - doesn't mean we can't choose to learn, study and take in new information - and as a consequence our beliefs may or may not change.
If a Muslim or Christian or Atheist says to someone "Believe this" - they can't simply say "Yes OK!"
If they give them information that convinces them - that's a different story. That is not simply "choosing" to believe - that is being convinced by new information. Very different.