>>7What are you trying to write?
Start with asking yourself that. There's plenty of prompts, games, journaling exercises, essay topics, and otherwise. I don't see why you can't start late. You might need to hone in on a style, but to me a lot of interest in writing requires a good breadth of experience and knowledge to draw upon. Knowing how stories are put together helps, but theory can be learned and only goes so far. Read, read lots and lots and lots. And if you want meta books it really depends on your approach. Hero With a Thousand Faces is a staple for a reason, and it'd probably be worth checking out if only to get a feel for such things. It's also nice to write something by the numbers in order to get an idea with how to operate within the rules before you break them. Anyways, I wish you luck on your endeavors.