Is it doing too much to delete a "family relation" on Facebook?

[BloopieBlooper]

Nope. Assert yourself, it makes you uncomfortable, the end. If she makes a big deal about it, she's really the one pushing boundaries. I suppose you could attempt one last time a quick email asking her to take it off because it's confusing to people who know your family situation and it makes you feel awkward. That way you are giving her the choice to delete it. If she doesn't then you do it. If she wants to make a drama out of it, well that's her deal. You're not sisters and you don't like it, The End.