You can start by doing an e-book, which is a lot less expensive, but a way to get published. You can promote it online and work your way up the Amazon rankings. Over time it can get very popular on its own without needing to pay a publisher to promote it.
Most people these days read books on e-books anyways, so you could just publish on the Amazon bookstore. You could later do a real paperback version too. You should be able to do it all yourself, but need to read how to do it properly so you are fully protected in case people want to copy it. Ask your parents for help too.