ponjee, we are all born atheists. Then, like you, many of us are subjected to religious propaganda when we are young and trusting in our adults. Many people never recover from that.
Some us do, mainly, as naomi says, by reading the bible, analysing it - in my case satisfying myself that the Jesus story is just fantasy - and realising that the gods are just delusions, and mainly unpleasant ones at that.
At that point we escape from that childhood indoctrination and become normally rational again i.e atheists. Simple as that.