For some, not all. There are those who go through the weening off period, and still have residue religious or mystical traits in them. I indeed call them residue religionists. New Age nonsense believers fall into this category, and some agnostics, I'm sorry to say. It's like they have a side bet on Pascal wager, kind of. But many of us never believed religious nonsense, not even slightly, not a scrap of it, even as children, even if our arguments were basic. There was no guilt or fear, just an internal knowledge that it was all crap. When we got older we were able to present mature arguments. If I had to guess I'd say our brains are not wired, meaning suspectible, to religion. If a person says they don't believe, but inside they sort of do, or at least a bit, or some mystical nonsense holds them, then there is problem. But if you truly believe it's nonsense, whatever your age, then you are free of it.

Started questioning Catholicism as far back as can recall. However the guilt clearly found a home in me.

I stated to leave religion when I was about 10. Was a full on Atheist by 20. Wasn't a college thing just figured it was what it is. A made up fable to control the population. If I was going to replace religion it would be with rational Free Thought. To me it's a no brainer.