I'm going to tell my project teammate that her quality of work is shit
Why do you want to tell your teammate that?
I think she is a lazy freeloader.
Even if you have heard things about her work, calling it shit will not help. It might tempt her to do shitty work and then you will have problems with your project.
Ok, I will tone it down a bit and use nicer words.
That is very mature. Being unnecessarily harsh may make people more resistant to change.