In reformed churches, we do not set an arbitrary age and admit an entire “graduating class” to the Lord’s Table. We wait and watch to see the work of the Spirit in our children’s hearts.
When they begin to show interest in communion, and consistently bear the marks of conversion, they should be examined by the elders and then received into communicant membership.
Posted below is a study guide and teacher’s notes that our pastor has used to prepare children for their examination. It can easily be adapted for homeschool use or a self-study.