You know that you're born again if you can see and enter the kingdom of God.... see the spiritual things of the bible and not just the LETTER.
John 3:3-5 KJV
Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God.
[4] Nicodemus saith unto him, How can a man be born when he is old? can he enter the second time into his mother's womb, and be born?
[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.