Some people, like the Catholics for instance, believe they are born again when they are baptised as infants. This is wrong teaching. You can only be born spiritually (be born again) when you see your need for Jesus and respond to his call. Now surely people will know if they've done that or not. Although there are those who say they are born again and we can't always tell for sure - but God can. My pastor friend Bob says that you can tell a wolf in sheep's clothing from their footprints.
scripture says baptism
Context of Jn 3:5 “born again”
John1:26 John answered them, saying, I baptize with water: but there standeth one among you, whom ye know not; (John prepared the way by baptism)
John 2:6 And there were set there six waterpots of stone, after the manner of the purifying of the Jews, containing two or three firkins apiece. (Old covenant prefiguring of baptism, purification from sin)(His disciples believed because the ever Virgin mother of God interceded Jn 2:11)
John3:5 Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God. (IBaptism)
John 3:22 After these things came Jesus and his disciples into the land of Judaea; and there he tarried with them, and baptized. 23 And John also was baptizing in Aenon near to Salim, because there was much water there: and they came, and were baptized.(Baptism / water)
John 4:1 When therefore the Lord knew how the Pharisees had heard that Jesus made and baptized more disciples than John.
Born again means Baptismal regeneration!