Responses
Her brother is first in line and it's not uncommon to exclude princesses or those not in succession to be knowledgeable about politics. Especially since it's a very peaceful kingdom. The prince probably also excuses her from government affairs not befitting of a princess.
Aaaah ok, that makes sense.
Seems promising for some real big character development with the female lead. From spoiled princess to becoming the sole kingdom's hope for the future. She'll have to probably learn everything that her brother had to learn up to that point. Although I question why she didn't learn all that stuff alongside her brother since she is also royalty.