As the saying goes, you must tie the bell to solve the problem. After you take the first step, take your girlfriend back in a month or two and let them get along for a while. You said that your girlfriend and you love each other very much, and she will definitely try to get on well with your mother. Step by step, she will slowly unload her mother's defensive psychology.
That's it. Take your time and untie the knot in your mother's heart.
Success belongs to the persevering. You should do well in both aspects. The most important thing is to tell your girlfriend clearly, so that she can see your mother when she goes to your house. Don't hold your breath. Tell your girlfriend all the pros and cons. I believe she is also a reasonable person.
I was touched to see you say you don't want to give up your girlfriend. Let's go