A Clarification.
To be technically corrrect, I am a Revert rather than a convert. That means that I was baptized Catholic , left the church as a young teenager, and thirty years later have returned to the Catholic Church. So it's not a conversion as much as a reversion, though it certainly feels like a conversion to me. I believe our lives are a series of conversions and though the "Damascus Road" experience is often profound and life changing, the conversion doesn't stop there but hopefully continues. Often times, our own conversions are more like Peter's: fraught with painful starts and stops, ecstatic "Eureka moments" , then flat out denials and turning away before eventually becoming what God intended.
How did my conversion start? The Bible says that the waters of baptism is what "doth save us" and Jesus and Peter both insisted on Baptism for the forgiveness of sins. So, I now believe my journey of faith technically started when Mom and Dad brought me down to the church as an infant for a 2000 year old sacrament that God used to confer His grace to me in. I later chose to walk away from that grace as a young teenager, but alas, He had already started a work in me through the grace imparted in those waters of baptism. John 3:3 has a very special meaning to me now when I understand Jesus to mean being "born of water" implies baptism. The Ancient Church had always understood that to represent baptism.
The operative word here in all this is Grace. We are truly saved by grace. "Since the initiative belongs to God in the order of grace, no one can merit the initial grace of forgiveness and justification." (Catholic Catechism(teaching)) Wow, you mean I received God's grace without anything I could do on my own part as an infant? Yep. You mean I didn't even say the sinners prayer and ask Jesus into my life? Nope. Too young, you didn't talk yet. You mean there was nothing on my own that I could have done to receive God's grace? Nope. He just poured it out on you! Well, that's truly amazing then. Yep! Amazing Grace.
If this whole concept is disturbing to you, try to put yourself in the sandals of a pre-first century Jew who knew that the only way for his child to become part of the tribe was to have a small section of redundant skin removed from a sensitive part of his body as an 8 day old infant. Hey , that's not fair, what if he doesn't want to become a Jew? He doesn't have free choice in the matter? He doesn't even get to say the Jewish Sinner's Prayer? Nope, God conferred citizenship into the people of God on the young tike through a physical act. Wait, there is something spiritual that happens through a physical action? Yes, that is a picture of what a Sacrament is. God conferring His grace through a physical means. The Jews were sacramental people and so is Jesus. Mud, spit, water, blood, oils, foreskins etc. Very messy things the Jews did. Yet our ancient faith was born from this. In conclusion, the early church didn't struggle with the concept of receiving God's grace (unmerited favor as an old evangelical would say) through the waters of baptism. I recently noticed for the first time when I reread the Book of Acts, that Peter's first speech after receiving the Holy Spirit included baptism for the forgiveness of sins.
He didn't ask the people to recite a prayer. He said "repent and be baptized everyone of you for the forgiveness of sins.. The promise is for you and your children..."