The little girl who lives in Home (Currently)

I have reasons to believe that I have a ghost in my house. It started over the summer, when my niece and nephew were visiting from Kentucky. My niece Bella would always cry at night because she said that someone was in the closet. One night I sent Bella and my nephew Tony to sleep around 11 pm. I checked up on them 10 minutes later and they were sleeping. So my sisters and I started watching a movie in my room, when all of a sudden the door to the room Bella and Tony were sleeping, opened. So I shut the t.v off so they wouldn't try to stay up with us. After 5 minutes the door closed, so right away I ran to see if they were up, and I just couldn't even believe what I seen. Bella and Tony were still sleeping by their Dad. It freaked me out, but I ignored it.
 I started discovering things. Little things like stuff being misplaced or even hearing things at night. I think that this ghost might be a little girl. I started to notice that my shirts were going missing, and it could be my sisters taking them, but I don't believe so. I remember coming home and one of my eyeshadow palettes were out. I know for sure it wasn't my sisters or mom because they don't like eyeshadow and it wasn't me because I haven't been using that eyeshadow palette.
 I finally told my mom what was going on and she would joke around and say "it's all in your head." It was not that long ago when my mom told me "okay, I believe you." My mom doesn't work Mondays, so she is usually home alone. She said she was hearing things out in the other rooms. So she decided to go to sleep, and when she was almost out, she felt someone climb on the bed. So is this little girl evil or just wants someone to know she is here....?