I am trying to figure out why you are so swift to judge it any sin at all. And please - a bit more than “honor your parents”. Honor is a two way street; if she feels so backed into a corner that she cannot discuss it with them, how is she supposed to resolve it?
Her actions are those of someone who needs to go one direction, but appears to be acting in fear. And if she is responding in fear, I fail to see any sin attached.
If I recall the op also was thinking it may be a big enough sin to step into a family situation they should not be involved in. I disagree with the idea that outside of financial information it is a sin. But convert99 can certainly opine on this thread. She thinks it’s a sin. And she may have a point. I still am not convinced.
Let’s not jump down her throat because she disagrees.
I don’t intend to jump down peoples’s throats. However, there seems a tendency to some to say Sin! Sin! without considering that there may be issues at play which remove the matter from sinfulness to issues of stress reaction.
To wit, from Convert’s post: “She’s sinning in not telling them (unless she is completely self-sufficient) not in the dropping out. But if she drops out, even if she’s honest, her parents may send her on her way and expect her to be self-sufficient or have a plan in place to be so.”
Not “she may be sinning” or “she could be sinning” but a bold statement “She’s sinning”. It is too easy to provide a simplistic response without considering that there may be other factors at work; and in this age of instant analysis and instant response, there are too many observers (including the OP) who could take this as some sort of absolute answer.
Convert’s comment about asking a priest may be the best answer, but the question should make us all consider that there are situations between family members which lead to less than desirable results, not because of evil (sin) but because of family patterns of interaction. An example: keep treating a young adult as a child, and you will not be happy with the eventual responses.