"You were brought up as a boy" is a variation on the "pushy female" or "unfeminine" retorts typically made by men who are fazed by an assertive, highly competent female ie. not somebody bossy for the sake of it, but a woman who understands the value of her own opinions and skills and does not automatically back off when faced by a noisy, aggressive male who either disagrees with her or who can't bear not to be in charge.
Broadly speaking, middle-class male upbringing (especially if it involves public school of any quality) leads them to expect to be in charge ("natural leaders") whereas working-class males still feels they ought to dominate but will probably have to do a lot more shouting and bullying.
Stereotypical female behaviour used to encourage much more manipulative behaviour (see 50s literature on the use of "feminine wiles" to snare men) and encouraged competition between women to weaken women's position vis-a-vis male dominated society.
Nowadays educated and middle-class women tend to be far more self-confident and aware of their rights, and the value of this self-confidence and sense of independence is recognised by the phenomenal rise of "Assertiveness for women" courses at all sorts of levels. Even educated professional women often find it difficult to make headway against groups of men, and that's why there is now emphasis on "networking" and "mentoring" for women, so individuals don't get ground down by the age-old male mechanisms for collectively dealing with threatening females. [Your aunty], incidentally, is a superb example of an assertive professional woman, as opposed to an aggressive harridan - restrained, usually quietly-spoken confidence in what she has to say (backed up by far more homework than most males will do).
Don't stand for being told you're "masculine". You're assertive and sure of your ground (well usually!) and you have a right to your ground (and to your share of the space, the discussion, and anything else that's going).
That's what the feminist revolution was about, and what all the critics who claim "it's gone too far" can't stomach. Going back to the 50s, or even earlier, will not solve the problems.