There’s nothing wrong with planning out your writing. Some people need it. Organizing things can keep you from introducing things in your first chapter that can kill plot possibilities for the conclusion if you’re not looking ahead.

Also, knocking out a detailed outline is a fantastic way to procrastinate getting any real writing done.

But avoid limiting yourself.

Roddy Doyle explains:

Change your mind. Good ideas are often killed by better ones…

Writers sometimes worry they have a limited amount of material and shouldn’t waste it. This isn’t true. If you’re meant to be a writer, the ideas will come. If you think of a better one, go with it.