Crying is a psychologically normal emotional response before the age of 3. Crying should be expected in very young children. However, it does not necessarily mean that something is seriously wrong or causing serious emotional difficulties. Crying is a normal and healthy response for kids of all ages. At the age of four, many children will go through different physiological and emotional changes. Hormones, growth spurts, moving from preschool to elementary school. These are just a few factors that could lead to crying in 4-year olds.