let's talk God parents.. need advice

Fast forward. I'm pregnant. And when I told her this, she announced herself on Facebook as the God mother of my future baby. And at my gender reveal party she made sure to make herself loud and clear about being a god parent.

My fiancé and I have decided that even though we are catholic, we are not following the god parent tradition (if the church allows us to do so and still baptize the baby). 

I am aware that I should just grow a pair and tell my friend this, but it's an uncomfortable conversation to have.. especially when she acts so thrilled to be the god parent.. however lately she has been acting very different since she's dating a new guy. He changed her. She makes no time for her friends or family anymore, and she seems to have no respect for herself or others unless it's the boyfriend. She is very dramatic and the attention always needs to be on her, or her relationship (even though half the time their relationship is completely toxic). I have tried addressing these issues countless times to save our friendship but it causes major drama filled arguments and she denies every single thing that is said. She doesn't think she has changed and she doesn't see a problem.

I know God parents have no legal rights over the child, but in our faith they are supposed to teach the child about our religion and be a role model figure. IF I chose to even have god parents in my sons life, it cannot be her anymore. 

So my questions are:

Is it wrong of me to refuse picking god parents for my child even though he will be catholic and baptized? / anyone out there who did the same for your children?

How do I address this situation with the friend and let her know that she is not going to play that role?

Thank you for any advice. This is stressing me out. 🙄