Very important to recognize that while Acts is historically accurate as to what happened, not all that was written down is to be done by us today, as was in a transition period.Keep in mind that Acts is a transitional book. Many of the things that happened in Acts are not normative for the church today. The Ethiopian eunuch was baptized by an Apostle, not a local pastor. He probably had an entourage with him, so his baptism would have been witnessed by others. He was baptized outside of the local church, which is not normative for today. Not everything is at it seems.