I have not read the book in awhile but I remember that Dicey was concerned that she would end up separated from her siblings. She has been trying hard as the oldest child to keep them together and she does not care where they live, but she wants the security of them being together.
The other thing that Dicey worried about was kids finding out much about her. She doesn't want them to know that she and her family are poor and have been abandoned by her mother. Docey has had to be the parent for her siblings for awhile even bfore their mother sent them away.