Paul said we are buried with Christ in baptism.Water baptism is a only a Symbol of that burial. It is ideal if it can take place immediately or soon after re-birth but that isn't always possible - it wasn't for me. I had been born again for about seven years before I was able to be baptised.
And I agree that not everybody that goes through baptism is born again. The do it for their own reasons or because their churches put pressure on them. And without the re-birth the baptism is all but meaningless.
If we are already born before being buried then we are buried alive.
Not cool.