What is the limit as the message did not say anything about that How to trim the list for the ones I want there to avoid messageYou've Reached the Limit  You have picked the maximum number of people and Pages to see first. You need to remove one before you can add District Crossfit.
Reached Limit of max number of people & Pages to See First. What is the limit & how to trim list?
facebook;facebook pages;followers;limit;follow
What is See First: When you select a person or Page to see first, their posts appear at the top of your News Feed.Limit: You can select up to 30 people or Pages to see first.For more see the Help Centre.Edit after OPs' commentHow to clear items from the list?From Help Center:To view your News Feed preferences:Click 'v' in the top-right corner of any Facebook page.Select News Feed PreferencesTo adjust your News Feed preferences:Click Prioritize who to see first to make posts from people or Pages appear at the top of your News Feed. Learn about see first.Click Unfollow people to hide their posts to unfollow a person, Page or group. Learn about unfollowing.Click Reconnect with people you unfollowed to follow a person, Page or group that you unfollowed in the past. Learn about reconnecting.Learn how to switch from top stories to most recent stories on your News Feed.