Responses
Some spoilers from the next parts
Though that is a point it wasn't the main reason. Her illness was the main reason. Since it's caused by magic and only nobles can have magic all the resources to treat it is only allowed for nobles. And without treatment she will die young. For her life and for her to chase he dreams, she and her family had to split paths as they wanted her to live long. And there was no other way to do this other than to let her be adopted. And once she is she cannot interact with them as it may endanger them and expose her secret
I thought that it will be a cute story but nope. It really irritate me when the MC acts like a child despite being an adult but sometimes it really pains me when she clearly missed her family but have to be separated. I genuinely couldn't find any reasons to keep reading the other books because of the separation.
It's disappointing when she had to leave her family just because she loves books that much.