I've created a series of books. I began (as I do most of my novels) with a single sentence. Now in to my fifth it's still going strong, although as I haven't found a publisher yet, strong is probably a subjective point of view.
Give it a go. Just start writing. Most of what comes out is gibberish, at least for me, but finally some kind of form appears and even if I never sell any of them, although I've had over seventy downloads of the free part from smashwords, at least I know I did it.
Then again, JK Rowling shouldn't become too complacent.
Feel free to have a look at Three Hoodies Save The world and give me your opinion if you've nothing else to do. I'm over twenty one and thousands of miles away so I can take it even if you think its the biggest pile of smelly stuff you've ever read.