Like it or not, even though r/s is between two persons, you
cannot ignore your gf's parents.And no matter what, they are your
gf's closest relative.
If u wanna get married, as a formality, have to go thru her
parents.
If you happened to get get married, her parents instantly become
your relatives.
When u got a child, besides your parents, they will become the
child's grandparents.
So, if she's the girl for you, no matter what's the obstacle ahead,
you have to face it.