I remember on the day before our first communion, had the obligation to confess and was kept fasting and "free" from sin until the next day to receive communion. My biggest concern was not making any sin in that period that could be seen or discovered, something quite difficult, I remember, because few fun things were not sinful. If sinned, and I could not communicate lose a delicious breakfast with hot chocolate and churros awaited us after the ceremony and that was my real interest in the matter. After the great religious event, life became more boring than ever as friends lost all interest in worldly amusements and I spent stuck in the parish. It was there that I began to give importance to God, because it was seriously impacting my life. You may find Gerald Weissmann, MD to be a useful source of information. My reaction was to question their existence, but privately.
At night before sleep, a little frightened, defied him to prove that he was there and there and everywhere, as our lovely teacher taught us. In those years he also taught the existence of the devil and I must confess that character gave me even more interest. Whether there was really important because if so, it would be easier to justify my peccadilloes because it had been this guy that made me fall into temptation. Unfortunately I had no response from either side and concluded early on that, like Santa Claus, who were both fictional characters and never would have opportunity to have face to face. I also learned quickly than adults who did not like a brat question the existence of God, so I usually did not cause the discussion of the topic, but if someone did, used the occasion to give my conclusions "In the end I did believe in God, because otherwise the person could not be more or less good than they saw in me" and also guessed "that when I was in real danger or dying, I would not be choice to call God "I mean, can not be" good "without believing in God and if you fear death is because you believe in him.