No, I think she's half Latina (Mexican, Puerto Rican, Venezuelan - I really have no idea)... but even if she wasn't, what's wrong with her using
Gianna?
I don't look at all Italian and I love that name and would use it myself. People who aren't Irish use Irish names all the time, so Italian names should be fair game as well.
"Chan eil tuil air nach tig traoghadh"
Capt. Malcolm Reynolds - Half of writing history is hiding the truth.
- Serenity