I'm glad I came across your post! Not a coincidence that I was just talking about this with a friend! My husband and I have a seven year old daughter, a 15 month old son and a baby on the way. So with our daughter we initially decided to go along with the Santa thing. However when she was about three we were going through major life changes. We did not see the importance of holidays especially ones that placed such a significance on material things. We were teaching her things don't matter, experiences are more important. So it didn't make sense to us to create this facade for her to play along with. We also did not like lying to her. Her whole childhood we taught her the importance of telling us the truth and being honest and here we were lying about something that literally did not even matter. When we told her she was four and she told me she already knew and didn't care! Our family actually cared so much more because they said we ruined her childhood. All I could think of is how silly that someone would think a made up person could ruin a childhood! I say do what you think feels right. I do not regret telling her the truth at all. This life is full of so much more than "Santa Claus" and I am so happy we get to share it all with our children!
Interesting that your family cared so much more and thought you ruined her childhood. Did you ask them why that was? Once I became a parent myself, I realized how important it was for me to have the correct answers to life's questions...and to not look like a hypocrite in the process. Truth discovery has become a big deal in my life for that reason. With that comes truth-telling. Unfortunately many people do not feel the same. Kudos to you being honest.