Girl's Behavior

What do I do about it?

I have a 35 year old cousin and she is a guest in our home with her mom right now. She is childish and acts like a man, already cuts her hair short like men I don't know why, just tryna explain her to you guys. I am a 18 years old girl and she's always coming after me at home, never leaves me alone, for example I go to my room and then she knocks the door then enter and says "Why didn't you take me with you" like? 35 year old girl should be sitting with elderly people at home, not supposed to come after me. She talks like she knows everything and judges me just because I don't eat from outside, no wonder why she is fat already. Now let me tell you what happened yesterday. She got out of my balcony and before she leaves my room, she sitted on my bed and said "let me see your hair dryer, maybe I can make the front of my hair like that" but she has 4 cm hair, she forgot her hair length while making up excuse to see my hair dryer 😅 I didn't even told her I have a new expensive machine because they gossip about it like "she made her dad buy that thing, poor man" so I didn't even tell about my machine but she understood it by its voice while I dry my hair, completely devil. Then I said "no no never mind I have to study now I don't wanna show it's okay" I was saying this in a kind way to prevent tension. But she insisted to see it with an offended face but it started to annoy me it was hard to make my face like I'm not disturbed, then she said "okay" got up angrily and slammed my door. She acted like that in my own home? What do you guys think? She doesn't even talk to me and yesterday when I sitted at the table she left the table.
What do I do about it?
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