Who TAUGHT you this?
Catholics didn't come along until about 300 years or so AFTER the 'first christians'!
New International Version (NIV)
19 Now those who had been scattered by the persecution that broke out when Stephen was killed traveled as far as Phoenicia, Cyprus and Antioch, spreading the word only among Jews. 20 Some of them, however, men from Cyprus and Cyrene, went to Antioch and began to speak to Greeks also, telling them the good news about the Lord Jesus. 21 The Lord’s hand was with them, and a great number of people believed and turned to the Lord.
22 News of this reached the church in Jerusalem, and they sent Barnabas to Antioch. 23 When he arrived and saw what the grace of God had done, he was glad and encouraged them all to remain true to the Lord with all their hearts. 24 He was a good man, full of the Holy Spirit and faith, and a great number of people were brought to the Lord.
25 Then Barnabas went to Tarsus to look for Saul, 26 and when he found him, he brought him to Antioch. So for a whole year Barnabas and Saul met with the church and taught great numbers of people. The disciples were called Christians first at Antioch.
Yep. And Ignatius of Antioch (bishop of that city who was familiar with the apostle John, and probably several other apostles as well) is the first person known to use the phrase "Catholic Church," about the year 107 in his letter to the Smyrnaeans (chapter 8). So did Polycarp, bishop of Smyrna (a student of the apostle John).
Catholics didn't come along until about 300 years or so AFTER the 'first christians'!
I guess our early martyrs Polycarp and Ignatius weren't 'first christians' then! If you read paragraph 8 of the link I gave you above, you'll see a very early historical source referring to the Eucharist, authority of bishops, and overall sounds quite Catholic.
Peace be with you.