You’re in good company! Some famous planners include Brandon Sanderson and George R.R. Martin. Planners prefer to be prepared before starting a project, and feel that their creativity is best expressed when they get to know the story before jumping in.
If this sounds like you, you might benefit from the resources on this site geared towards planners, such as extensive help with outlines, brainstorming, and character development. But feel free to explore all resources and use whatever feels right for you. Writing is a very individual process, and there’s no one way to do it!