The reveal, or being privy to it prior to the narrative disclosure, is not so important as the unfolding of the character's own understanding and what it represents to him, dramatically. Even the reveal itself was reflective of character ... it reinforced and enchanced everything that came before, rather than invalidating it.
Really, I'm just trying to say that people put too much stock in twist endings, to the point of missing the actual purpose of the work.
Audience-superior moments are often used to great effect. You and others who elected to "guess" the ending simply had an unintentional audience-superior experience. Doesn't necessarily say anything about the effectiveness of the story up to the point where you were "validated."