That church started at a Pentecost was an entirely Jewish assembly. Headed at the time by a Jew. They sold their possessions and goods and had all things common together. And there isn't a gentile anywhere to be found there in their midst on that day of Pentecost.
There was a church started there for sure. It just isn't yours, and never has been.
That all changed when the Holy Spirit filled the upper room.
The Jewish leadership had rejected Jesus as the Messiah foretold in the OT. Saul before his conversion, from a Jew to a Chrsitian, was part of the stoning of Phillip.
After Pentecost, believers in Christ Jesus increased daily. The Church spread over Judea, Galilee, Samaria, and into all the surrounding countries. It was at Antioch, the capital of Syria, that the faithful were first called Christians, because they were believers in Christ, sealed in him as their Lord and master.
Before that the early converts call it The Way to distinguish between converted Jews and Jews.
The Gospel was first preached only to the Jews but for the most part they were not accepted. It was the will of God that the gospel first be preached to God's chosen people, as Christ Jesus himself did. Many Jews were converted but usually not from the leaders, who persecuted the Christians (as Saul did before his conversion). Christ had foretold the destruction of Jerusalem, and the Roman army, under Titus, in the year 70 destroyed Jerusalem. The destruction of the temple, the center of God's worship in the old covenant, signified the end of both the old law and the unity of the chosen people who did not accept Christ.