We'll be christening our dd1 and dd2 next summer. Dd1 turned three a good month ago and the other day I tried to explain to her why she will be christened but got completely stuck! We aren't an overly religeous household and dd1 hasn't actually been to church before (this Christmas will be her first time). She knows about Jesus and that he was "a very special person and helped lots and lots of people" (that's roughly how I've put it to her) but I haven't even tried to explain the concept of God to her yet.
So, any ideas and own experiences on what kind of wording might help my three year old to understand the meaning of being christened would be appreciated!