It was kind of a slow burn. Every time I heard a new argument against the existence of God, I’d repeat to myself, “Just because I can’t think of the answer doesn’t mean there isn’t one.” You can only say that so many times before it starts to feel like you’re being stubborn.
Probably the most compelling argument was, to me, the contradictory nature of an all-knowing God existing in the same reality as free will.
I decided I was an atheist (logically) a long time before I started to feel like an atheist (emotionally). What pushed me over the line there was when it was pointed out to me the sheer arrogance of looking out at the massive, incomprehensible scale of the universe and saying, “the creator of that really cares about me in particular.”
So now I say I’m an atheist, somewhere between gnostic and agnostic. I can’t rule out the existence of something that could be called God by someone’s definition, but I’m confident the abrahamic god, the one I grew up with, can’t exist.