I'm going to ignore my girlfriend
Why would you ignore her?
I ignore her every time she's mean to me.
It's rude to just ignore people, especially partners and even if they were mean to you first.  She may leave you if you continue treating her like this.  Try talking through your problems rather than the both of you being immature about it!
I don't care if she leaves me.
Well, then it may be the best thing if she does leave you or you leave her. No one should have to endure an abusive relationship.