I saw a ghost when i was younger.... (what did she want? Read!)

Ok. i lived in this house when i was younger & i woke up one night to noises (a girl talking) & i was the only girl in the house because my mom was at work & my older brother watched me, & i went to his room & he was sleeping, so i woke him up & he told me to go back to bed (LOL)
then a month later i was home alone waiting for my aunt to pick me up & i was in the livingroom watching TV & i looked in the hall way & saw a girl (about in her teens?) her hair was in a ponytail, she was wearing a tanktop & Jeans & she walked out of the bathroom & into the computer room but before she went into the computer room, she looked at me & smiled (she seemed nice & friendly) then walked into the computer room, so i turned off the TV & went outside to wait for my aunt because i was scared of what would happen to me if i stayed in the livingroom or if i went to look into the computer room.
after we move, she never showed up again

why did she smile at me
why was she in that house
what do you think she wanted

I like Alexis answer. most ghost (even though seemingly nice) are almost NEVER nice. there are some rare cases though. Now to answer those questions huh? 1. she could have smiled at because you could see her, as not many people can. 2. it is not known for sure but some believe that ghost linger in houses because they either lack the ability or requirements to leave. 3. she could have wanted any number of things on that one, you guess is as good as mine bud.

Maybe she just wasnt ready to leave yet, maybe she was trying to trick you &then later harm you...I'm not really sure but I do believe in ghosts