I want to start reading to my child. Any rules? How long should I start reading to her? She is 6 months old. Is it too early to start reading?

I ever read somewhere and through personal experience , I can tell you that toddlers concentration span are short; so try short stories. Perhaps till they are much older, you can introduce longer stories. If long stories, you can try a few pages each day, increase as they grow older. It's definitely not too early to start. Actually what you do now is only to simulate their brains and to cultivate their interest. Doubt they will understand the story now!