Game of Thrones 1-75

From what I understand there is a North and a South separated by a wall.  About 12 years ago there as a war and the South was taken over.  Now Dany, a 12-13 year old girl has to marry a Lord so her brother Visery can get an army from him to take back the seven kingdoms that used to belong to his family.  Robert, the King of the South, asked Lord Stark, the Lord of the North to come to the South and be his kind’s hand.  Lord Stark agreed after a conversation with his wife and is bringing along three of his children.

So far I am a little bit confused about what is going on, but it is definitely starting to get good.  Something that bothers me is how young the girls are when they get married, also the fact that they don’t have a say in who they marry.  The men are very dominant in this book and women are there mainly for their pleasure it seems.  I loved the fact that Lord Stark kept Jon and loves him so much even though he is a bastard.  Although Catelyn is mean to Jon, his father only wants the best for him.  I found it odd that brothers will marry their sisters and have sexual relations with them.  It is because they want to stay within the family but I found it very strange.    

            Winterfell kind of reminds me of where I’m from.  I grew up in Minnesota and winters there can be brutal.  Every time they talk about the North and winter coming it makes me think of home.  I can understand how hard it is going to be for the children and Lord Stark to leave their home for the South.  You come to love the cold and it is hard to leave home.

            One question I have is, how did the seven kingdoms of the Dragonstone come to war and get taken over, and is King Robert the one that took it over?

            Another question, what is the significance of the wall? Is it there for protection, to keep something out?