Sure right after you show me incontrovertible proof of ANY Christian Church existing before the Catholic Church, right after you show me incontrovertible proof of any Christian Church that was involved with the assembly of the Bible, the establishment of the Apostles' creed, the Nicean Constantinople Creed, the defining of the incarnation, etc.....
However, there was a Christian church that existed before the Roman Catholic Church.
25And he left for Tarsus to look for Saul; 26and when he had found him, he brought him to Antioch. And for an entire year they met with the church and taught considerable numbers; and the disciples were first called Christians in Antioch. Acts 11:26 NASB
I can also point to the Day of Pentecost in Acts 2 when the church was born through the outpouring of the Holy Spirit.
We also see the early church in Paul’s letters as well. But no Roman Cathokic Church mentioned.