No, no mistake. Obviously, Jesus WAS talking about a "second" birth, was he not? Nicodemas thought Jesus was talking about a repeat of the "physical" human birth, but Jesus was speaking about - AND he corrected Nicodemas on it - another kind of birth, a spiritual birth, a birth that was "from above" and not physical human birth. So, Jesus did say you MUST be born again and that birth was from above. When we come to saving faith in Jesus Christ, we are born again into the family of God - we become His children through faith and we have a new spirit nature within us. In order to go to heaven we MUST be born again.
Jesus was talking about Spiritual conversion. Birth is a metaphor.