There are two kinds of repentance and one of them simply means a change of mind. Before anyone could be baptized with water he had to believe, as witnessed by the following exchange between Philip and the eunuch:
"And as they went on their way, they came unto a certain water: and the eunuch said, See, here is water; what doth hinder me to be baptized? And Philip said, If thou believest with all thine heart, thou mayest. And he answered and said, I believe that Jesus Christ is the Son of God" (Acts 8:36-37).
Before the eunuch was baptized with water he was already "born of God" because he believed that Jesus is the Christ, the Son of God:
"Whosoever believeth that Jesus is the Christ is born of God..For whatsoever is born of God overcometh the world: and this is the victory that overcometh the world, even our faith. Who is he that overcometh the world, but he that believeth that Jesus is the Son of God?" (1 Jn.5:1,4-5).
There can be no doubt that the eunuch received eternal life and was "born of God" before he was baptized with water. Then he submitted to the "baptism of repentance." That baptism was in regard to changing one's way of living for the better.