I'm not arrogant, I'm experienced. I was diagnosed many years ago when you actually had to have significant symptoms, and have witnessed the recent shift of the past ten years to diagnosing absolutely everyone with autism, no matter what their real problems are.
These people have zero in common with those of us who were diagnosed a long time ago. Mostly, they can live independently, and have unpleasant personality traits that cannot be explained by poor social skills. In fact, they tend to have good social skills, which they explain by "masking".
They also take over autism groups and center themselves, while judging autistic people with more severe symptoms than them as lazy and failures. They think they are superior, because they officially have the same label, so when they see that they can have a career, education, family and home, while others can't, they think it's because they are vastly superior and have overcome the challenge of autism. In reality, they have very mild or no autism and were less disabled in the first place.
In my opinion, personality disorders are being misdiagnosed en masse as autism. Professor Uta Frith agrees that narcissism is being misdiagnosed as autism, and there is a study suggesting that EUPD and autism presents similarly in adult women. Nobody wants a diagnosis of a personality disorder, while autism is fashionable and a lot of people use the label to bolster their egos.
In my experience, people with traditional (diagnosed a long time ago) autism almost always cannot live independently without help. It seems OP's daughter is doing this during term time and there has been no mention of anything that would suggest impaired executive function.
Her only supposed autism symptom appears to be that she is selfish while thinking everyone else is unfair to her. She remembers this unfairness for a long time, which sounds very much like narcissistic grudge holding. She also falls out with friends and never accepts fault. Again this does not sound like autism.
If she has NPD, an autism diagnosis will do nothing except enable and embolden her. Not only that, but she will then be suggested to join autism groups, which if she joins will be harmful to people with real autism.