If she does not acknowledge the fact that you have been taking unnecessary blame or at least, show some vunerability and begin opening up the discussion with you.......then.......I agree......put up a boundary and stick with it. This might be as simple as saying:
"Well, I won't be doing that any more." (re taking blame) and ending the conversation.
A co-worker of the opposite sex keeps making comments to you (maybe even about you) that you find offensive. You smile and walk away or give a little chuckle from the awkwardness of it.
This teaches them that they can keep getting away with it or keep pressing your buttons. Instead, I would say, You know, I take offense to that (specific comment or action). I want you to stop OR If you don't stop, I will _________________.