I want to be an actress, but just can't find a good drama school!?

I really want to take an opportunity to follow my dream, but can I do that without actually taking lessons? I read everywhere that if you don't, you won't know what the directors will be expecting you to know already and not get cast for the majority of the roles because of the lack of experience. Can someone tell me what to do. And if you could find me good drama cles for teens, I live in Derby. Thanks.