Why does she act different?

Alright so I met this girl, she's the sister of a friend. We met and started talking (in real life) then we also drove my car for fun. After talking and all she started to ask for my age cause she said I looked good.

We then hung out at her place with some friends, including her brother. She had some alcohol but the whole evening she was asking for my attention, she touched me, had her legs over me. Then she began about what's hers and she said I was hers and said I was gonna sleep next to her, even tho I said I couldn't. She kept saying it.

Then when I left she got into my car, she looked at me and hugged me and tried to kiss me. I turned my head away and she went like why? I said I didn't know if you wanted to..
Then I made a joke and said then do it again? She started joking and said mehh tomorrow better luck
Day after, we texted about hanging out. We did, first it was the 2 of us but then our friends joined (Wasn't very happy with that). Well so then we had a minute or so alone and she asked me something, after that she said "You didn't want a kiss" but then after she said that she walked next to me, talking with me, also with my friends but with me she walks really close to me and tries to touch me and says she wanted my attention.

We still planned to hang out the same day but the 2 of us. Well then she went like nah tomorrow cause she was tired. Well I got a bit annoyed.. I later on even texted her that. She said "plans can always change🤷‍♂️"

She acts different.
Why does she act different?
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