My short story shows it as rated by people in the category of young adult, religious and literary fiction the last category of which is ok. My story is not really geared to young adults and definitely not religious. It's a Christmas drunk story, Should I be using the age feature?
Unless your story is targeting a specific age range, I'd leave the ranges blank.
If you already have set a range, to undo them, set each of them back to "Select".
And, of course, nothing happens until you work your way all the way through to Save & Publish (obviously you don't have to re-upload anything if all that you're doing is changing metadata or pricing, etc.).