Hey Forest...
Jesus tells us in Jn 16: 7 KJV "Nevertheless I tell you the truth; it is expedient for you that I go away: for if I go not away, the Comforter will not come unto you; but if I depart, I will send him unto you."
It's just not possible for a person to have been born again or born of the Spirit while Jesus was still here. And to take that idea one step farther, I'll add that the new covenant was not as yet inaugurated because Jesus was still alive and a testament is not in effect while its testator lives. For myself, I suspect that the new covenant didn't become active until Jesus presented his blood to the Father in the true temple in New Jerusalem which the Lord himself pitched.
I used New Jerusalem rather than heaven because scripture tells us that New Jerusalem is the mother of us all. : )
It is my belief, that the scriptures teach that the old testament saints are born again in the same manner as the new testament saints are, with the indwelling of the Holy Spirit. One of the verses that reinforces that is Isaiah 63:11 - Then he remembered the days of old, Mosos, and his people, saying, where is he that brought them up out of the sea, with the shepherd of his flock? Where is he that PUT HIS HOLY SPIRIT WITHIN HIM?
God is a 3 in 1 God. The Father, the Son, and the Holy Spirit, each having a different function. My belief, according to the scriptures, is that the Holy Spirit, also, has different functions. He indwells us as a part of being born again, He reveals the truths of the scriptures to those who have been born again, and He is a comforter to the born again.