This question has it’s roots on the show but isn’t based on it necessarily. Cersei tells Ned “your just a soldier, your brother was taught to lead and you to follow”. My question is how different either in Westeros but more specifically medieval Europe would the education difference be between a first and second born son?

warsofasoiaf:

A noble boy’s education encompassed reading and writing (in our history it was Latin, in Westeros it’s the Common Tongue), grammar, logic, rhetoric, philosophy, astrology, music, and mathematics, in addition to military command. In warfare, they would often be called upon as lieutenants for their father and older brothers when needed, often given critical roles as befit their station. So no, I don’t think the education would be so different, leading their unit in battle would be expected for them and so they need to learn strategy, communication, and so on.

Thanks for the question, Anon.

SomethingLikeALawyer, Hand of the King

I think the teaching is meant to be more metaphorical than literal: Ned’s formal curriculum wouldn’t have been different, but his socialization would have been.