Confirmed Catholics are in many databases, all over the world.
Wherever you were baptized, that’s where your records are kept. It gets fun when a parish closes or gets merged! Then you have to find out where they were sent.
Anyway, wherever you were baptized has your name in a registry. And you should have a certificate somewhere as well. So when it’s time for First Communion or Confirmation, they’ll ask to see your baptismal certificate. And after the fact, they notify your baptismal parish. Same with Marriage or Holy Orders.
When you try to get married in the church, they won’t accept your original baptismal certificate; they’ll want a recent copy. I went through it a few years ago. Fortunately, we had my original Baptismal certificate, and my mom still attends the same parish. So she toted the original down, they looked it up quickly because it had all the relevant data on it, and a week or so later we got the fresh copy. Why does it matter, you may ask? Because it will also show when and where I got Confirmed, and also show that I was never married in a Catholic church. And if I had been married and it was found null, that would be on there too. The original only shows I was baptized.
If anyone reading this doesn’t know for sure where or when they got baptized, now’s the time to start pumping the relatives for information, or start looking through the old photo albums for clues. I know a guy who* thinks* he was baptized Catholic, but his family never went to any church that he recalls. His mother’s dead. His father told him “I think it was St Mary church…”