my best friend is a ***

You know how people change as they grow older. It just stinks so damn much. So I and this girl used to be so close. We'd tell each other everything. We'd cry together and stand up for each other. But now, she has turned into a total whore. She used to be a somewhat rebellious person that liked ''good'' music. She used to hate everything that she is today, but I guess not.
She hardly talks to me anymore. She's only with the people that will get her the most attention. She's still my best friend though. It's just that, since high school, we've kind of drifted apart.
She dated this one kid over the summer. A very nice boy. They went to movies together and slept over at each others' houses. They had fun together. But when school started...ooo, she just couldn't be seen with him anymore. She couldn't date him anymore because people made a big deal about it. She had too much going on to be dating. Then she promised us and herself that she'd never date again.
What's this? Not even a month later, she goes out with this other dude, and at the same time leading her ex on. She has her ex haul her everywhere. To the movies, his house, home, football games, and she knows he's not even a legal driver. She calls him everyday for hours and makes him say "I love you" to her. Everyone tells her to knock it off, but oh no, she's "just friends" with him. At games she would tell him that she just wanted to stay in his car. Then she talks to her boyfriend while her ex is sitting right next to her.
Well, she finally stopped leading her ex on because she wanted me to stop calling her a whore and stuff, but it's true. I hate when people change. I hate it so much. Now all she cares about is pretty boys prancing around on stage and how many boys she can get to go after her.
It just makes me sad that she can't listen to me anymore. She's my best friend and I hate her.