John 17:1,5
You assume that because the Son is speaking here that He was also called the Son when He shared His glory before Creation. The verse does not say that. It is Christ's spirit speaking here in the body of Jesus, just as the Spirit of Christ spoke in and through the prophets. 1 Peter 1:11 The truth appears to be that He was called The Word before Creation.
Hebrews 1:1-2 In these last days, the days that Hebrews was written, Jesus was known as God's Son. However, when God made the universe through Him, which we read about in Genesis 1, we do not see the term "Son" or "Son of God". What does it say in Genesis 1? "Let US make man in OUR image, according to OUR likeness; ..."
Who is US? John 1:1 "In the beginning was the Word, and the Word was with God, and the Word was God."
Hebrews 1:8-12 In the context of verse 5, the author is speaking of the resurrected Christ, which Paul confirms in Acts 13:33. Then he goes back about 33 years in verse 6, and is speaking of the physical birth of Jesus. Then in verse 10 he refers once again to Creation, Genesis 1, where the terms "Son" or "Son of God" are not found.
Colossians 1:15-19 Jesus is called the "firstborn of all creation" and the "firstborn from the dead", which have the same meaning, i.e. the first one to be resurrected from the dead with an immortal or glorified body. Again, Paul confirms that "Today I have begotten You", from Psalm 2, is Christ's resurrection from the dead. Acts 13:33, also called here in Colossians 1 the "firstborn from the dead". Jesus was before all things, but not as "Jesus", or as the Eternal Son, but as "the Word".
John 3:17 "For God did not send the Son into the world to judge the world ..."
If my interpretation is correct, then it could be stated something like this: For God did not send the Word into the world to judge the world, but that the world should be saved through Him - which would be quite confusing. Did the Word die on the cross to save the world? No, it was the "Word" that "became flesh", Jesus, the One who became the Son of God, that died on the cross. John called Him the "eternal life, which was with the Father and was manifested to us - ..." 1 John 1:2
Civic - Please quote the verses that include the term "the Eternal Son".
Civic - Also please explain why in Luke 1:35, that Gabriel says, "... and for that reason the holy Child shall be called the Son of God."
For WHAT reason?
So John 3:17 is stated the way it is, to make it clear Who we are speaking of. In one sense, Jesus did not pre-exist. He came into existence inside Mary's womb, as a human baby, but also as the Son of God. In another sense, Jesus did pre-exist as the eternal life or the Word, which was with the Father. The Word was miraculously transformed into human flesh - yet at the same time He did not lose His identity, nor did He cease to exist.