Caffeine isn't good for adults so if a child has it it's not good for their health. Children are to young to have coffee.
Why can't kids drink coffee?
It's because of the health risks involved, it increases the heart rate, and the blood pressure too much in young people, meaning kids, it can cause you to shake uncontrollably as well. Some kids who have drank too much coffee or energy drinks sometimes need to go to the emergency room because of heart problems. Hope this helps.