You have never met a born-again Christian

John 3:7 (KJV) Marvel not that I said unto thee, Ye must be born again.

These are the words of Jesus spoken to Nicodemus (a Pharisee and ruler of the Jews) during Jesus' earthly ministry. 

Note the singular pronoun "thee" and the plural pronoun "Ye". The former is used in a phrase addressed to an individual, and the latter in a phrase addressed to the member or members of a group. Written out more fully the verse becomes, Marvel not that I said to thee (Nicodemus) that ye (Israel) must be born again. 

This is a reference to the creation of the nation of Israel:

Exodus 4:22 (KJV) And thou shalt say unto Pharaoh, Thus saith the LORD, Israel is my son, even my firstborn:

Having been born at the exodus, the nation of Israel needed to be born again in order to be reconciled to God after it had gone astray. 

Once Israel fell (which it did after it stoned Stephen) this was no longer pertinent.

In the dispensation of grace, this is what happens:

1 Corinthians 12:13a (KJV) For by one Spirit are we all baptized into one body,

So while you may have met someone who has been baptized by the Holy Spirit into the Body of Christ, you have never met anybody who has been born again in the scriptural sense.