Interracial relationship racist mom

[lumpisan]

Ok so heres whats been going on. My Gf is black and i am white. not a big deal. we've been dating for baout 7 months now and are really close(ie weve started saying we love each other). The problem, is my mom is to put it lightly batshit insane about me dating a girl of a different race. She actually brought up the "purity of our familys blood" and how" i am disgracing my ancestors" which i know is bs but whatever.
the problem isw my gf wants to meet her and im not sure how to tell her because shes alil sensitive to people being racist.
so im kinda in a rut right now idk what to tell her