Although being born again is to water baptized into the body of Christ but the water you mentioned in John 3 is referring to water from a woman: the womb.
Galatians 3:26-27 King James Version (KJV)
26 For ye are all the children of God by faith in Christ Jesus.
27 BECAUSE as many of you as have been baptized into THE SON OF GOD have put on THE SON OF GOD.
This baptism baptizes a believer into the ressurected body of Christ and so it is written of the ressurection of Christ, Thou art my Son; this day have I begotten thee.
Acts 13:33 King James Version (KJV)
33 God hath fulfilled the same unto us their children, in that he hath raised up Jesus again; as it is also written in the second psalm, Thou art my Son, this day have I begotten thee.
Remember in Matthew 20 when James and John's mother asked Jesus to allow her sons to sit one on His right and the other on His left?
Jesus first says - you have no idea what you are asking; and then says "....are you able to drink of the cup that I shall drink of and be baptized with the baptism that I am baptized with"?
Now do you know what "cup" Jesus drank and what "baptism" he was baptized with?
Your answer actually comes out of the verse in Galatians here that you quoted. "As many as are baptized into Christ are
baptized into His death."
So what was the "baptism" Jesus had to be baptized into.
He had to die. That was His "baptism".
Now what was the "cup" that He drank? That one is a little more directly answered in Revelation. Chapter 14 talks about the "wine of the wrath of God"
19:15 talks about Jesus "trending the winepress of the wrath of God" Psalm 78:8 speaks of a cup of God's wrath.
Jeremiah 25 also talks about the "wrath of God" as a "cup".
Matthew 26:39 talks about Jesus having this "cup" to "drink". He prays that the cup pass from him. Yet, not my will but Yours be done.
Back in Matthew 20:
James and John answer "Yes we can." And then Jesus says to them "You will drink of my cup and be baptized with the baptism I'm baptized with..."
James and John are not capable of enduring the wrath of God and being put to death to atone for sin; yet "in Christ" they suffer what He has suffered. This is how they (and all believers) are "baptized into His death".
Now the proof that Jesus overcame the wrath of God and conquered death is that He rose from the dead. This is why it says "Therefore
we are buried with him by baptism into death: that like as Christ was
raised up from the dead by the glory
of the Father, even so we also should walk in
newness of life." Romans 6:4
That has nothing to do with water. The water is just a symbol.
"And such were some of you: but ye are
washed, but ye are sanctified, but ye are justified in the name of the Lord Jesus, and by the
Spirit of our God." 1 Corinthians 6:11
"Not by works of righteousness which we have done, (like water baptism) but according to his mercy he saved us,
by the washing of regeneration, and renewing of the Holy Ghost;" Titus 3:5
Now here comes a question "at ya" that's going to sound really stupid. It's a "Yeah duh." question: Who is all powerful in the universe? (Obviously the answer is God. Yeah duh!)
Now of the power of God; what is being dunked in a pool of water going to affect of His Divine decree? If you are sealed unto redemption by the Holy Ghost. If you are washed and regenerated unto redemption by the Spirit of God; than you
ARE part of the body of Christ. There is no question about that. Nothing can take you out of the hand of God almighty; even if you are not baptized before you die! God is sovereign over all of it; and there are people in this world who are not afforded to be water baptized. That does not mean they are not legitimately saved.
I presume you have not been a Christian very long? And I'm just curious - why have you not been baptized yet? What are you waiting for, or what is "the church" waiting for?
I'll tell you a little story here:
My son is now 17 years old. When he was 9; he came to me and said he believed in Jesus and he wanted to be baptized. So I told the pastor of our church and his response was "The elders want to make sure he has a credible profession of faith."
Now nowhere in the Bible does it ever say that they waited to baptize someone. Usually upon profession of faith; they were baptized that day. There was no waiting to see if the "profession of faith" was "credible". You say you believe the gospel; we baptize you. If you turn out not to be a believer in the end - that's between you and God.
So we waited..... and waited....... and .......waited... (seven years passed)!
Now my son has autism and epilepsy. He also has a certain degree of "behavioral problems". He gets frustrated easily and "runs". He can't sit through an hour church service without being a distraction. Yet I know this kid's faith is real, because he's not afraid to die!
Having epilepsy and having a malformed blood vessel in his brain; he has been confronted with his mortality on several occasions. He has faced this in faith that he is secure in God's hands, even if this kills him.
Yet this church we were attending neglected to baptize him for the sake of preserving their own traditions. (Now there's a particular individual who rose from the dead who has a BIG problem with that!) "For by your traditions you make the command of God of none effect". Matthew 15:6
So last year my son was baptized at a Christian music festival we've been attending now for the past 3 years.
At any time in that 7 years, he could have had a major health crisis and died. Yet nothing - even the lack of obedience to the command of God that this church exhibited could separate him from the redemption Christ secured from the foundations of the world. (Revelation 13:8)
So yes, being water baptized is part of obedience; but in no way does it affect our salvation, or our being welcomed into His eternal body!