How can I be a successfull actress?

right so im only 12 and i have absolutely no experience in acting, not even at school because the things we do at school aren't very interesting. I really want to become an actress but don't have a clue how to get into showbiz, I want cles but don't no if my mum can afford it. We have acting lessons at school but I barely learn anything the only time I really ever actually act is after watching a film and I sort of re- do the scene in my mirror. Please help, it is my dream to become an actress and the younger you start out the better!