The Bible is clear: believers are to be water baptized.

In fact, in many cases throughout Scripture, baptism occurs immediately after believing in Jesus, at the same time of their conversion to Christ.

"Sirs, what must I do to be saved?” And they said, “Believe in the Lord Jesus, and you will be saved, you and your household.” And they spoke the word of the Lord to him and to all who were in his house. And he took them the same hour of the night and washed their wounds; and he was baptized at once, he and all his family. Then he brought them up into his house and set food before them. And he rejoiced along with his entire household that he had believed in God. ' Acts 16:30-34

Water baptism is a public declaration, both to the physical and spiritual world, that you belong to the Kingdom of Heaven. There is power in this, as seen in Acts 2:38, where the gift of the Holy Spirit is given following repentance and baptism

"And Peter said to them, 'Repent and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit.'" Acts 2:38