i don't think it is she is hiding you because she doesn't love you or feel the same or is embarrassed to introduce you, it is clear it is her parents that are her concern not you. why don't you ask your common friend? they should know. she might worry her parents will kick her out and that scares her. have you ever met other family members just not the parents? they all can't have the same issues, or maybe she is scared they will tell her parents. you should discuss it fully with her so you are fine with not meeting them. all should matter to her parents is that you a nice person and treat their daughter well and respect her and love her.
When I tell the truth, it is not for the sake of convincing those who do not know it, but for the sake of defending those that do.
William Blake