My girlfriend barely feels anything with penetration. I am also female, so it doesnt feel necessary, as such, but I was wondering if it is a medical thing, as literally, when I was demonstrating what I like, she could not even feel which side of the vagina I was pressing against. She said she feels a little at the entrance, but otherwise virtually nothing.

Is it just that penetration isnt for her, or is this extreme lack of sensitivity a medical issue?