Some folks who call themselves Christians don’t know where they came from or WHEN?

A friend I sang in a choir with some years ago told me he knew Jesus did not exist before he was born on Christmas day in Bethlehem. I shared scripture with him to convince him how wrong he was but God’s word didn’t move him at all.
In Ephesians 1 Paul writes, “Praise be to the God and Father of our Lord Jesus Christ, who has blessed us in the heavenly realms with every spiritual blessing in Christ. 4 For he (God) chose us in him before the creation of the world to be holy and blameless in his sight. In love 5 he[b] predestined us for adoption to sonship through Jesus Christ, in accordance with his pleasure and will.”
In Psalms 139 David writes, “My frame was not hidden from you
when I was made in the secret place,
when I was woven together in the depths of the earth.
16 Your eyes saw my unformed body;
all the days ordained for me were written in your book
before one of them came to be.”
If we are ever to know and understand our true identity in Christ, we need to know and believe in our hearts that God created each believer in Christ, and He created each believer before the foundation of the world.