That's all I know so far. I learned that from the Mass in B minor, by J.S. Bach. Possibly my single favorite piece of music.
An excellent start. Listen to Bach some more or get yourself an old missal, it's not hard. Actually, it is a great idea to read the old Mass in English, then you will understand why people love it. You are in our prayers, best wishes with RCIA, my husband did it too.
Dude, that ain't Latin. It's Greek. Yes, even the "Traditional Latin Mass" has those three sentences in Greek. Here's some Latin for you: Agnus Dei qui tollis pecata mundi miserere nobis. Agnus Dei qui tollis pecatta mundi miserere nobis. Agnus Dei qui tollis pecatta mundi dona nobis pacem.
AB