When Jesus told Nicodemus he needed to be “born again,” the phrase wasn’t new to him. In Pharisaic Judaism, several major life transitions were described as a kind of “new birth.” So Nicodemus wasn’t confused about the idea of being born again — he was confused about how a person could experience such a rebirth later in life.
Resources:
Nicodemus
Living God Ministries - Nicodemus https://share.google/1uOJGEbSuc5mgnm3Q