Italian is a beautiful language and well done for wanting to learn some before you go. However operatic language is different from ordinary spoken language and the words don't sound the same. I have difficulty understanding the words in an English opera.
You could buy a good used 'box set' version of a popular opera and get one with the libretto included. This will give you the words and a translation. A DVD will also give you subtitles in the original language.
This has double sub-titles.