Why doesn't Jane try to figure out who Grace Poole is?

Jane is very curious about Grace Poole and her mysteriousness.  Instead of  inquiring more about her, or trying to confront her, she ignores the curiosity. Jane is pretty sure that Grace Poole lit Mr. Rochester's bed on fire, but she doesn't tell anybody. It seems unlikely that she wouldn't try to figure out the mystery that is Grace Poole.