Born of water = natural birth (from your mother) Born of The Spirit = spiritual birth (born again.)
Water baptism is an outward ritual.
First, when a baby is born, they are not born in water. It's amniotic fluid. That is not what Jesus was talking about.
Secondly, Jesus was describing what it means to be born
again. He was describing a spiritual birth. And that birth involved water and Spirit. It is obvious that you cannot be born
again unless you had already been born once. Jesus further clarifies thi point in verse 6 by making a distinction between natural birth and spirit. He said that which is born of flesh is flesh and that which is born of spirit is spirit. Flesh cannot inherit the kingdom of God so you must be born again.
John 3:5 is a parallel verse to John 3:3. Jesus said the exact same thing but he expounded on what it means to be "born again" in verse 5. Born again in verse 3 = water and spirit in verse 5. In the same way as "see the kingdom" in verse 3 = "enter the kingdom" in verse 5. Surely you wont say that he meant something different by "see the kingdom" and "enter the kingdom." Neither did he mean something different by "born again" and "water and spirit."