Sorry, call me a liar but I do not believe that you had some innate, inborn knowledge of God and how to pray without first having some exposure to prayer and God in the first place. You may have learned it at school, as at that time prayer was incorporated into schools. Even when I was a child back in the 1970's in the South, prayers were said over the loud speaker in the morning in my school.
I trust you were not born in China. America is not a vacuum of Christianity. It is all over the place, and probably more so when you were a child. It would have been pretty easy for you to pick up bits and pieces of the Christian faith in American society at the time.
Babies and infants have no knowledge of God or prayer until they learn it through the example or indoctrination by other people. Otherwise why would not children all around the world be believers in the Christ and God of the Bible when they turn 8 years old. Your logic is screwy.
Though I don't remember of my teachers praying in school or of my early school teachers advocating Christianity, likely there were references to God in some of the text books or history lessons relative to the founding fathers. In some of he patriotic songs and things like the Pledge of Allegiance there were references to God but not to the point that I had a particular awareness of them. Most of the stories were things like Dick, Jane & Spot or fairy tales, etc. At Christmas it was all Santa. Certainly prayer or Bible reading was neither in the school or home in my experience.
I never heard the term "born again" until I heard it in church. We lived in the country in Wyoming and I never experienced a flush toilet until the 2nd grade, though the year before we moved to town our home had a flush toilet. The one room schoolhouse had a wood pot belly stove and an outhouse. All 8 grades were taught in the school house. When we moved to town that all changed. That was during grade 3.
I don't remember of prayer in our home before we went to church. There was a little prayer I prayed before bed time as a child, but to the best of my recollection that was after we began going to church. It was the one, "Now I lay me down to sleep; I pray the Lord my soul to keep. If I die before I wake, I pray the Lord my soul to take." ....or something like that.
BUZSAW B 4 U 2 C Y BUZ SAW.
The immeasurable present eternally extends the infinite past and infinitely consumes the eternal future.