I really doubt that when they told you they said, “Because you are girls you have to wear dresses” if they did then I agree.
But one thing I think that girls/women have to learn is that not everything that is not fair is sexist. Such as at our school girls/women are not allowed to teach certain classes or make some speeches, why because they are girls/women. This is not fair but no one complains, its just the way it is.
I also wouldn’t run around putting yourself with the feminists because they are really not a good group to be a part of (in my opinion) They are avid complainers and constant annoyances. One thing I am waiting to see is a group of men who complain because of the unfair treatment put at them, I have never heard of such a group I wouldn’t doubt that one exists though it isn’t like men are always treated fairly. In conclusion life isn’t fair live with it.
Take this and leave me,
Proverbs 26:27
If a Man digs a pit, he will fall into it
If a man rolls a stone, it will roll back on him.

(I hope you have the basic knowledge to realize that by man it means PERSON not male in gender)