Um.....
The Son IS God (as is the Father and the Holy Spirit).
See John 8:58. See John 1:1-18 where the Bible says that the "Word" is God and was at Creation and then equates the Word with JESUS (not only the Son). Also see Jude 25 and 2 Timothy 1:9 et al
There is much mystery here.... stuff beyond and outside the normal concepts of physics. Yes, Jesus was incarnate at the Annunciation (celebrated on Monday) but JESUS (100% God and 100% man) ALWAYS existed as such; remember that the Divine Nature "communicates" (the theological word used) with the Human Nature.... the two natures being INSEPARABLE (although not blended)... so that the Bible is right: JESUS was present at Creation, long before March 25 of the year 4 BC. If you can't wrap your brain around this, join the club - NO ONE for 2000 years has been able to do so, which is why it's called "the MYSTERY of the Two Natures of Christ." IMO, best to just accept what God says as God says it - and shut up. God knows. God is correct. That's good enough.
This is fundamental orthodox ecumenical theology. Here's a Baptist speaking briefly on this, Dr. John Piper,
https://www.desiringgod.org/message...the-word/excerpts/before-time-began-jesus-was
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