Children are completely capable of a mature relationship with the Lord.
Many of the materials written for today's children reflect a mentality that approaches children by dumbing down everything. didn't He say "Let the little children come unto me. . ." ?
Children can be born from above. Children can have solid prayer lives and they can learn to trust and recognize Him for themselves. There has been an unhealthy creeping growth of modern Christianity. Entertainment has been valued over Truth and there is a born-again culture that is a parallel culture in Western countries.
Have your children memorize. Teach them songs that have meaning. Introduce them to those who have gone before - men and women who displayed character, faith and who were eager to spend themselves for others.
Teach your children about Jesus. Talk about Him. Sing about Him.
Most importlantly, pursue and love Him with all your might.