When the ruler of the feast tasted the water now become wine, and didn't know where it came from (but the servants who had drawn the water knew), the ruler of the feast called the bridegroom,
Now, John was, by physical birth, a cousin to Jesus. However, John was born before Jesus was born. Probably in about the sixth month of Mary's pregnancy when John was born. Yet, John is saying of Him, "He is preferred before me: for He was before me." So, he is talking about that pre-existence of Jesus prior to His incarnation.