Welcome to puberty!
It arrives earlier with each generation, and as Lottie says, this is not too early for this behaviour to start.
I have three daughters, so i do know how dreadful this time is.
You need infinite patience, and an endless ability to see life from your daughter's point of view.
Thos raging hormones mean she hates herself, and the world, inclduing you, at various times, and is confused by how she feels - when you ask her why she behaves this way and she says she doesn't know, she is speaking the truth, however frustrating this sounds.
So try and ride out the bad times, and capitalise on the good times. In her good moods give her lots of affirmation, that she is a good person, and that you love her, and make some time for 'girlie' times like DVD's and shopping.
She needs to know that she is not a freak, and that her feelings are OK, but bad behaviour and disrespect is not. Paradoxically, she will appreciate the firm boundaries because they will make her feel secure, even if she will never tell you that!
Give her space and privacy - eseential at this age, and make her friends welcome - encourage her to have friends round, better she is at home than roaming, as so many youngsters are.
You need to stay calm and be firm - impossible at times, but she will learn by example, as all children do.
It would be great if children could go to bed one Friday night, and wake up as adults on Saturday morning. Sadly, the transition is a little longer than that - say up to about eighteen, but hang in there, she will be dipping in and out of her personality and being some horrible alien who looks and sounds like your daughter, but she will come back, I promise!
You will all get through this, and believe me, all teenagers are the same in varying degrees, so don't worry, and if you need advice, there is plenty of experience on here, so post away!