Why did she push them away? Because she was afraid. She was afraid that they were going to leave her, just as everyone else had. She was scared of trusting them because the only ones she had ever trusted had left her.
It wasn't even just a fear of losing them. It was the fear of them leaving her for someone else, someone better. So she tried her hardest to be better. She studied hard to be smarter, but not hard enough. She had to be as good as him or he would realise that the difference between them was too much. That she was way out of his league. But no matter how hard she studied, she couldn't seem to get it.
She tried her hardest to be prettier. She starved herself whenever she could without anyone noticing, she styled her hair to hide as much of her face as possible, she wore sunglasses to hide behind, she hid behind baggy clothes so that people couldn't see her lack of curves. But she could never compare to the other girls.
She tried her hardest to be more talented. The only talent she wasn't bad at was singing, and she did it so much that no one ever cared anymore. Her other talents were minor, especially compared to others.
She tried her hardest to have a cool personality. She tried to be nice while maintaining her mystery, tried to be smart enough to come up with good comebacks. She tried to be the one who was always smiling even though inside she slowly dying. She tried to be entertaining. But everyone thought she was boring.
She tried her hardest. But it would never be enough.