At a very young age I was put into a Christian school. Ironically, none of my family members are Christians. In fact, the decision was taken due to the fact the school had a good educational level.
At the beginning, (I'm not scared to say this), I was into religion a bit, but after a while, and specially after I started getting more and more into mythology, science and philosophy, I became rebellious. Not in a violent manner. I simply started arguing with my the teachers about the possibility that religion was purely an human concept, and that god didn't really exist.
If you don't believe, and if you hold a position when it comes to what you belief, you should definitely show your view to others.
My wife is from a Muslim family from Morocco. When I met her, she was a believer in what she thought, was the right thing for her. But with logical arguments and clearer ideas I came to show her other possibilities. I never imposed my view as being the "truth". But simply showed another possibility.
And concerning Christmas, we simply don't celebrate it. Not like most families do. For us (me and my wife) is a time in which we simply get closer after an hectic year.