As soon after they are saved as possible. In the Bible, people who were saved were baptized shortly thereafter.
Then those who gladly[a] received his word were baptized; and that day about three thousand souls were added to them. Acts 2:41 (NKJV) But when they believed Philip as he preached the things concerning the kingdom of God and the name of Jesus Christ, both men and women were baptized. Acts 8:12 (NKJV)