The sacraments were given to the Church; they are not for private consumption, administered by anyone. Not just anyone officiates entrance into citizenship in a nation (baptism) or enforces exile from it (excommunication). Jesus gave the keys of His Kingdom to His apostles (Matt 16:19) who passed them on to elders (Titus 1:5). (Pages 177-78).
Abraham received the sign and seal of the covenant of grace: circumcision (Gen 17; Acts 7:8; Rom 4:11). Being uncircumcised was a sign you were a stranger to the covenant of promise (Eph 2:11-12).
Baptism is the circumcision of Christ, or signs and seals it, so that it replaces circumcision as the sign and seal of the covenant of grace (Col 2:11-13).
The Spirit makes baptism effective as a means of grace, as evidenced at Pentecost (Acts 2:33, 38-39).
In Acts, the Spirit was grafting new Gentile branches into the tree of Israel, calling primarily for adult baptisms. But the pattern of giving covenant children the sign of the covenant had not changed. Where is THAT in Scripture? If the credo-baptist points to the circumcision of the heart, then why baptize at all, since it is the heart that matters?