Many parents are excited to get their young children started in school, but English researchers have found that sending kids to school too early can be tough on their mental health. They looked at over 2000 elementary school students aged five to nine from 80 schools. They found that children who are younger than their peers, and closer to the minimum age cut-off for starting school, tend to perform poorly in class and require more special attention than their classmates. They are more likely to experience worry and fear, have poorer relationships with their peers, and have behavioral and concentration issues. They conclude that 3 years is an ideal age for kids to start school, but they stress parents must consider other factors: whether kids are toilet trained, can sit still for short periods, can communicate their needs and listen to others, and can spend time away from their parents.