Is Maggie Tulliver a moral person?
I would argue that she is certainly a moral person as she has very strong feelings about right and wrong and worries quite a bit about other people's feelings and making sure to do right by people.
One clue towards her being more moral, perhaps, than some others in the novel is the conflict that goes on constantly between her and her mother's family. They are always concerned about her hair or her looks, and she feels that they ought to be able to rise above such superficial concerns.
She is not perfect, by any means, and her constant rushing into things leads to a variety of mistakes, but the important thing is that she is trying her hardest to do right by people, even when she does end up hurting them.