Is my cousins room haunted or am I seeing things?

[Sexi-Gal]

Well I was in her room with her and then she needed to go and get something I think, and then the window burst open. I shut it but it was really stiff and I had shut it just earlier that day and it was fine. Then as I turned around my cousin was standing at the door like a statue and there was a mist behind her (like fog). I was really shocked and I fell back onto her bed. When I went to pull her into the room ( trying to get this mist away from her, as I was scared because of they way the color was draining from her face ) But yeah, as i pulled her in the room, the mist disappeared, The color came back in her cheeks pretty soon but not mine, she decided that she had forgotten something and I was begging her not to leave me alone (the store cupboard they have is so "special" to her and im not aloud in there...) but she did and then as she turned the corner to go downstairs I saw this woman down the hallway and she was walking towards the room but then i screamed, my aunt rushed back up and as I saw her the woman disappeared. I told her everything and she said it was nonsense. Do you think she was right?