At what time in you religious formation did you finally come to the conclusion that it was not what you were being told. Many Markers out there and mine started when concepts such as "Infallibility, Transubstantiation" The 10 Commandments and the Parting of the Red Sea will make you scratch your head a few times. Did Noah really find two of every creature, or build the ark.
I look back now that I have been atheist for about 4 years and realize the 100s of times that I struggled with what was obvious flaws in the thinking. I only had to overcome the hurdle of abusive indoctrination through finally coming to understand that I wasn't evil and dumber than everyone else. I was honest to a flaw and the "rebellion" they saw in me was that struggling to get past the pschological affects of being badgered into submission.
That comes from holding your true feeling inside for too long knowing that what you truly felt was or wasn't religious was going to be attacked by others. You don't have to struggle with the obvious which the others are totally blind of because they lace the ability to challenge or discuss the obvious. Being a constructive skeptic does not equate to being thought of as a rebellious. Condemnation of others entails Rebellious, Hateful retorts which ensures that their is to be no further discussion.
For me it was when I was a about sixteen and decided that if I was going to continue to say that the Bible was the word of God, the least I could do was read it thoughtfully and objectively as possible. So, I did, cover to cover. That pretty much did it.
I want to say that I was in my early teens. Listening to pastors and reading the bible myself...
I noticed how much of the bad shit preachers tend to skip over.
Then I started noticing how many contradictions there were in the damn thing...
I realize that it was all bullshit.