But when the fullness of the time came, God sent forth His Son, born of a woman, born under the Law,
so that He might redeem those who were under the Law, that we might receive the adoption as sons. –
Galatians 4:4-5 NASB
I don’t know any details of God that He hasn’t shared with everyone but I take the clause here “… in the fullness of the time ….” to apply to history.
Jesus was born when God, the Father, planned; not before, not after; His birth wasn’t hastened or postponed by anything.