How do you kow if a ghost is nice or not?

Okay so theres this ghost who i cant see but i can hear them in my head if you thik im crazy then whatever but its true. sometimes this ghost tells me to do random things like on night i was outside at like 1am when i wasnt supposed to be and i was going to go inside but the ghost told me to stay outside a little longer. a few seconds later my mom walked right past the door and didnt see me. if i would have went inside she would have gotten mad but she never saw me thanks to the ghost. is it a good ghost or not? im not sure even though he did help me