Most families will start the habit of family devotions when their children are between the ages of 4 and 10. A lot happens in this age range, but in general, children in this range still want to be read to - but are ready to think through the ideas we find in scripture. Our family teaches the preschool class at our church twice a month, and I can tell you our little 3-5 year olds can grasp and grapple with some pretty big faith concepts.
Our family's favorite devotion resource for families with children in this age range is Susan Hunt and Richie Hunt's Big Truths for Little Kids. This book combines the story of a family with catechism memory work. Each of the 36 chapters tells a piece of the family's story and introduces several catechism questions and answers.
Catechism memory work is a centuries old method of teaching spiritual truths by memorizing questions and their answers. This memory work gives us a strong foundation in principles of our faith.
Question: Who made you?
Question: Why did God make you and all things?
Answer: For His own glory
There are many different catechisms, this book uses First Catechism - Biblical Truths for God's Children. It is specifically written from children, but parents will learn a lot to as the questions develop in complexity over the course of the book. Our family used this book when the girls were 7 and 4 and we greatly enjoyed it. We still fall back on catechism truths that we memorized during that year.