The aunt couldn’t inherit the bloodline since her brothers were first in line. She got married afterwards and lost her right to inherit, so even when her brother died she could not receive that title so she depended on her children. However, since her dead brother was still first in line his kid would be first in line (before the aunts’ children), and his only child happened to be a girl. So in this case heritage comes before gender and Avery is allowed to receive the title despite of her being a woman solely because of her blood and her not having any (male) siblings.
Ohhh I get it now. I thought the aunt is the eldest that is why I thought she's first in line but since she's female, his brother became first in line hahahaha thaaanks (≧∀≦)
I know someone posted a comment already about this but I forgot who and when hahaha... why is that the aunt can't inherit the title but her daughter(when his son refused the title) or the female lead can? Is it a matter of time? Like in their days female cannot inherit it but now they can??? So kinda confuse because with all the drama of simply being a women and all but in the end they can hahahaha or maybe I didn't read thoroughly the story hahahaha sorry (￣∇￣")