Based on this description, Mary seems to be a curious girl, as she wants to find out the source of the crying noise. She also appears to be independent because she is making decisions that are different from those that are suggested to her.
We cannot assume she is disobedient and rebellious because we do not know whether looking for the source of the noise was prohibited. Perhaps she was told to ignore it as an advice, not as an order. She is also not afraid as she goes investigating on her own. Finally, there is no indication of the noise being at night, or of it having any impact on her sleep.
