When do you teach children about God?

When my kids are young, I pray with them everynight. My 2.5 years old son can make a simple pray by himself. For older child, I will read bible story with her occasionally since she shows interests. She is attending a church kindy and thus she has been exposed to God since young. For me I think as long as your child understand a simple story, you can tell them about God through bible stories. There are a lot of young children version of bible.