Many dear souls think that they have been born again because they have joined the church and have been baptized. Every saved person ought to join the church and be baptized, but joining church and being baptized does not make one a Christian. Water baptism is not designed to give birth to your soul. Only God can give birth to a soul.
Water baptism is a symbol, and is designed to picture death, burial and resurrection.
Remember that water baptism made no change in Judas Iscariot, neither in Simon the Socerer. The only change these men had was a change of clothes. There must be a change in heart in order to be saved. Without Bible assurance of your salvation you could neither be happy nor useful. You could never be happy with the thought that you are saved now but that you might be lost tomorrow.