Having the name of the holy God placed on me in baptism I literally became a "child of God" so that God is indeed my Father in heaven. I was baptized into Christ, into His death and resurrection. My sin and death were buried and I was raised to new life in Christ. This is the life of the forgiveness of sins flowing from the atoning sacrifice of Jesus on the cross. I was given the Holy Spirit, the very Spirit of life.
Christians and Christianity are taking a beating - not only around the world where they are killed simply for being Christians and not only from secularism that denies what it cannot see - primarily, we take a beating here and now when we, thinking a need for another baptism, forget that we have already received God's Spirit. We lose greatly when we divide the Holy Spirit, the same Spirit that we received in Holy Baptism, or look for a new spirit. Living in the one baptism we have already received, we sin, but we are not left without the Gift God has poured out on us. When the sacrament has been properly administered there is never again any need for those who have been baptized to be baptized again, ever.
We hurt ourselves greatly when we separate God from His work, His gifts of salvation for us. We also divide the one Spirit when we are tempted to think that another baptism will better the last or be more truly that of the Spirit. So the Apostle reminds and encourages us to be "careful to keep the unity of the Spirit in the bond of peace. One body and one Spirit; as you are called in one hope of your calling. One Lord, one faith, one baptism."
One baptism connects us to the one Lord in the one faith through the one Spirit. If, in baptism, God gives eternal mercy to helpless infants and those who have come to the faith later in life then faith says, "leave it at that." Rejoice in the Gift you have received. Return to it to be washed from your sins. If you are baptized maybe the best reason not to be baptized again is that baptism does not depend on you. Once is enough. He knows what He is doing and He is looking out for you, not just today and not just for fifty years, but for ever.