You can change your post preferences as follows.
From All-Ages to R-18
1. From the menu, open your Creator Preferences
Go to "Posting R-18 contents" and click "Edit"
3. Check "Yes" and click "Save changes"
From R-18 to All-Ages
Set all your posts to private before completing the following steps.
1. From the menu, open your Creator Preferences
2. Go to "Posting R-18 contents" and click "Edit"
3. Uncheck "Yes" and click "Save changes"
4. From the menu, go to Manage Posts and re-publish the posts you had set to private
*Please make sure your posts do not include R-18 content.