Views can include website data collected before the view was created.

Analytics automatically creates one unfiltered view for every property in your account, but you can set up multiple views on a single property. Views do not include data before the view was created. You can add up to 25 views to a property. Tip: When you delete a view, that particular historical perspective of the data is gone. When you add filters to a view, the data you exclude is unavailable.