According to the Bible, all believers are to be baptized in water, just like Jesus himself.
To be eligible for baptism in water one need only to believe in the Lord Jesus Christ and have made a commitment to follow him.
Baptism doesn't make someone a Christian. It shows that they already are one. We do not baptize children unless they are able to understand these matters and make these choices. Any child who wishes to be baptized must first attend a one-session class with a parent or guardian.