Girl's Behavior

Am I wrong? Why is she acting like this?

I’m the new guy at school. I’ve become really close friends with this one girl who’s been here a while. I took her out with me and we really connected. The rest of our classmates noticed how close we were and started making fun of us/making little comments. I felt uncomfortable so I pulled away from her and focussed on other people and another girl. Now the girl I was close to stays away from me and avoids me. She won’t even look at me. The other girls are mean to her. I try to include her with them but she just leaves. I even heard her talking on the phone about another guy she’s dating.

Am I wrong? Why is she acting like this?
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