Well, by your imagination, who was the first Catholic, as in member of the Org (rhymes with Borg)?
That is a non-sequitur and an obfuscation. But Scripture does give us a clue:
“Jesus replied, "Blessed are you, Simon son of Jonah, for this was not revealed to you by flesh and blood, but by my Father in heaven. And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.” Mat 16:17-18
Since Scripture says Christ built His Church on Peter, I'd guess Peter was the first catholic.
And interesting that Sola Scriptura is never mentioned in Scripture, but was 'revealed' by flesh and blood, ie, Martin Luther - 1500 years removed from Christ.