Girl threatened to sue me?

So I’m in uni and in a group project with a girl who threatened to sue me after I said I’d expose her to the rest of the class so they’d avoid working with her after she basically called me every bad name in the book and swore at me so badly and tried to blame the lack of work and team cooperation on me when I’ve been the most cooperative.

My friends jaw dropped reading the messages this girl sent, she was literally saying really disgusting things about me all because I told her to fuck off when she started criticizing me. After I told her I can’t wait to show the rest of the class her messages and that I already took screenshots she said “yeah so I can sue for defamation you worthless bitch”.

Should I be worried about that? Or is it just an empty threat?