In several years, you will look back at moments like these and realise how silly they are.

I'm sure we, at the age of 12;13, weren't the mature people yet we are now (hehe). At that age you're not meant to be mature.

I know you just said it because you were frustrated, you're not the first person/kid to say such things, being angry. But stay away from the 'wishing your parents were dead' though. Try to think on it longer than a minute, how your life would be like if they died tomorrow.