Jesus existed with the Father in the beginning, as the "Logos", not as flesh.
John 1:1, "IN the beginning was the Word, and the Word was with God, and the Word was God."
Ten times in Gen. ch 1, God used Jesus to create the Earth and everything in it. "And God said...".
John 1:14, "And the Word was made flesh...".
Luke 1:35, "...that Holy Thing, which shall be born of thee, shall be called the Son of God".
This was the beginning of the Son of God, as flesh.