So disappointed in my daughter....13

Ladies... I need to vent because I have never been so disappointed in my daughter.

Shes wanted to have a sleepover for her 14th and I said yes. She invited 7 girls over. I had seen most of them over our house at least once but there was one I haven't seen. Her names was Joy. I assumed she was just a new friend. I may be wrong but by Joy's behavior she did seem like she was on the spectrum. Very sweet girl though. During the whole sleepover I had noticed my daughter and her group of friends were leaving Joy out. They would all go outside and leave Joy in the living room. I kept telling her "Hey you forgot Joy". "Don't leave out Joy". They were also being very mean to her and talking about her looks. I kept saying "Knock it off, thats not nice". They also wouldn't let her be in their TIKTOKS. It seemed like her and all her friends were ganging up on this poor girl. I kept telling my daughter and the girls to stop being mean. There was some commotion at around 3am and I went to see what was going on. My daughter and her friends were laughing and Joy had went outside and was crying. I had to kind of investigate what happened. My 16 year old son heard most of it because the sleepover was being loud and keeping him awake, but Joy ended up having an accident while she was sleeping. Her mom didn't tell me she had a bedwetting issue. She had bought a pull up but it went missing from her bag. She had an accident and my daughter and all the girls were being horrible to her and making fun of her. My said said he heard my daughter tell her that nobody likes her and I really hope he's just saying that to try to get her in trouble because I can't imagine that I raised someone like that. They had bullied her to the point she went outside to cry. I went to talk to her and she said she wanted to go home so I drove her home. All the girls left today and I haven't even figured out how to talk to my daughter about this. My husband had always said our daughter was mean but I just figured she was just had a loud mouth. I'm honestly wondering if they just invited that girl to bully her but I hope my daughter wouldn't stoop that low.

Edit: The reason I didn't send the girls home right away is because it still was my daughters birthday. Also I'm not completely sure why my daughter invited her so to say it was 100% just to bully her isn't fair. I plan on talking to my daughter but a lot of you guys are hating on a 14 year old like you were never mean in your preteens.

Edit#2: Why are you guys acting like I did nothing! I said IN MY POST I had told them to include Joy and to knock it off. I also personally feel the last part could have been avoided if her mom just told me Joy has accidents. Idk why she didn't even bother mentioning it.