When should a child who professes faith begin to partake in the Lord's Supper? Because of the severe warnings concerning eating and drinking in an unworthy manner (1 Corinthians 11:27-32), it is important to consider whether a particular child is mature enough for the appropriate self-examination that is necessary in coming to the table.
Here is a helpful article that I encourage you to read, especially if you have young children.
It is an article by David Michael, one of the pastors at Bethlehem Baptist Church in Minneapolis. Why Can't I Have a Snack Like Everyone Else?