In Islam, men are not superior to women, and there is a provision for women as well. The closer you are to the deceased (by blood) the larger your provision is. Additionally, what you get from your inheritance is solely yours to spend, whereas all blood relative males who received part of your dad's inheritance are bound by religion to use it to take care of you and your sister, and take on all financial responsibilities of your father in addition to whatever they may spend on theirs families. Also, wills are NOT haram- it's a bukhari hadith that a muslim should not let two nights pass without making a will about it, no matter how much or little he has.

For judgement, NTA because it seems like your uncle's would not take care of and provide for you and your sister, but the misinformation in the post irks me.