If you are affected by the way your mother has parented you and are having issues with that parenting where the boundary lines are slightly blurred then you are going to have reactions and they are going to be angry reactions.

Just because your mother didn't do the unthinkable does not mean that other boundaries were not crossed and that would evoke a response from you which compromised your feelings and concerns.

You are obviously trying to "normalise" the relationship with this girl but the behaviours from your mother as you grew up would be creating anxiety and friction within you and so creating the same anxiety and friction within any relationship.

I suggest a counsellor to begin with and if the counsellor cannot get through the wall they will send you to a psychologist or psychiatrist, who would help you to rebalance things and sort them out.