Being born anew in John 3 is to receive God, who is the Spirit, and Christ, who is the life-giving Spirit (1 Cor 15:45), into your human spirit, to be joined, mingled, with Him, the Triune God, to constitute one spirit (1 Cor 6:17), which is to make one a member, a part, of the Body of Christ (1 Cor 12; Rm 12), to be His expression and counterpart (Gen 1:26; Eph 5), to express Him and satisfy Him for eternity as the New Jerusalem. It is to receive, so as to possess permanently, irrevocably, and ontologically the divine life, which is contained in the divine Person, which is God Himself, the I Am, but also contained in and joined to the Son of Man, with His sinless, perfect, created, glorified humanity.
The Son of God, Jesus Christ, was and always has been born or begotten of God since He is eternal, without beginning (Heb 7:3), and His Father is eternally His Father. He's never not had the divine life because He both eternally receives eternal life, and He is eternal life. Jn 1:4. He's the Resurrection and the Life. So He's never needed to be born anew. He's always new. There's an ancient expression of Them: "Always a Father, always a Son." Being born anew isn't to start over with your human life: it's to become an actual and "natural" (versus adopted) child of God through receiving and becoming one with God's life in the most interior part of your being.
Although Adam and Eve, before they sinned and became full of sin, both needed to be born anew---now there are only sinners. Thus only sinful human beings can be born anew, through forgiveness and justification by Christ shedding His blood, which permits the righteous, holy, and sinless GodMan to enter into us, mingle with us in our spirit, and begin to spread to and transform our entire being: spirit, soul, and body, conforming us to Himself. Glorification, the culmination of this experience, salvation, and process, is also compared to birth in Romans 8---although us believers' regeneration (being born anew in our spirit) is in 8:16 particularly.
For the anxious watching of the creation eagerly awaits the revelation of the sons of God. For the creation was made subject to vanity, not of its own will, but because of Him who subjected it, in hope that the creation itself will also be freed from the slavery of corruption into the freedom of the glory of the children of God. For we know that the whole creation groans together and travails in pain together until now. And not only so, but we ourselves also, who have the firstfruits of the Spirit, even we ourselves groan in ourselves, eagerly awaiting sonship, the redemption of our body. Rm 8:19-23.
God, the Son of God, is born eternally. There's an eternal flow of life (and love) from Father to Son. The Son of God was born into Mary's womb (Mt 1:21; Lk 1:31, 34) in conception through the Holy Spirit to be Emmanuel, God with us. The Son of God was delivered by Mary in the manger (Mt 1:25; 2:1; Lk 2:5-7, 11). There's an ancient and modern expression calling her the "mother of God." Of course she's not the source of His divinity (1 Cor 11:8), but she did then gestate and deliver God incarnate (Lk 1:42-43).
Birth imagery and words also describe Christ's resurrection. That's Romans 8:29 and Colossians 1:18. "You are My Son, this day have I begotten You" is the prophecy in the Psalms, repeated three times I believe in the New Testament. Referring not to Christ Son of God before He became a man (Jn 1:14), and referring not to His conception in the womb or birth in the manger; but referring to Jesus' resurrection, where His created part--His human life, body, being, nature: His humanity--was "officially" designated Son of God. Christ never stopped being God, the Son of God; He never altered or "changed" His divinity; and He always was, and is, one person. But He did become a man and add humanity to divinity so as to save us, men (and women), and become our Savior, both judicially and organically, both objectively and subjectively.
Paul, a slave of Christ Jesus, a called apostle, separated unto the gospel of God, which He promised beforehand through His prophets in the holy Scriptures, concerning His Son, who came out of the seed of David according to the flesh, who was designated the Son of God in power according to the Spirit of holiness out of the resurrection of the dead, Jesus Christ our Lord. Rm 1:1-4.
Now we do not yet see all things subjected to Him, but we see Jesus, who was made a little inferior to the angels because of the suffering of death, crowned with glory and honor, so that by the grace of God He might taste death on behalf of everything.
For it was fitting for Him, for whom are all things and through whom are all things, in leading many sons into glory, to make the Author of their salvation perfect through sufferings. For both He who sanctifies and those who are being sanctified are all of One, for which cause He is not ashamed to call them brothers, saying, "I will declare Your name to My brothers; in the midst of the church I will sing hymns of praise to You." Heb 2:8-12. (See also Jn 20:17.)