There is nothing as fragile as a child's psyche.
Child psychologists will tell anyone that the most formative years are those from birth to about sever years old.
While some may be of the opinion that children should not be exposed to "religion" during their formative years, there is enough proof that those who are brought up with a sense of right and wrong during their early years become better and more well adjusted adults.
We are no talking of religion "per se" here.
Teaching children about God at their earliest age -- if done the right way -- brings out more confident, behaved, well adjusted and loving kids.
Yes, there are those who feel that teaching about "hell" and the "devil" to kids may be harmful to the child's psyche IF not done the right way.
Truth of the mater is that teaching about Jesus is good because Jesus has no single teaching that can be considered "bad for kids".
When one takes into consideration the message of Christ, it is simple, pure and applicable to all kids no mater their particular religion.
Perhaps the beauty of Jesus' message is that it suits children.
After all, it was Jesus who said that unless we become like kids we may find it difficult to enter the kingdom of heaven.
God's love is a message that makes kids more secure as they go through their life.
The begin to have faith that there is SOMEONE loving them who created the heavens and the earth, yet at the same time cares about their individual lives.
Starting teaching kids about God the moment they can understand the most basic things is giving them the moral and Christian foundation to later trek the right path as they grow older.
You also get a better behaved child who loves his/her parents; interacts better with his/her peers and respects his teachers.
Now, aren't those enough reasons why we should teach children about God the moment they notice the beauty of His creation?