Though your child may be mentally ready to begin kindergarten, she may not be physically ready. Some children are simply not developed enough at 4 years old to properly hold a pencil or write cohesive letters, which may affect the development of her writing. Entering your child early may actually place her behind other students in other areas, such as physical education. The size of a child can greatly affect her role in the classroom. By waiting a year, sometimes a child develops more so that she is caught up with other children. Some children are naturally smaller than others, but early placement can further hinder naturally smaller children.
Placing your child in kindergarten early may hinder him socially when it comes to adolescence. Even though your child may be mentally ahead for his age, his emotional maturity may lag behind those who are a year older than him. This can affect dating and even casual friend relationships between your son and his peers. Before you enter him into kindergarten early, evaluate his behavior at home. If he has more control over his temper and does well at listening and following directions given by adults, then he may be ready.
Sometimes placing your child in kindergarten a year early does them a great service. Some children are mentally and emotionally ahead of other children their age. If you enter your gifted daughter into school early, you will be placing her with kids who are performing at her level. This may prevent her from skipping grades in the future. For some children, skipping grade levels can be traumatic, as they are forced to basically leave behind formed school friendships and create new ones.
Placing your gifted child into kindergarten early may positively affect her life path. Because she is at the "correct" level of instruction, she should be less likely to become bored in school, resulting in fewer behavioral problems. Also, she will be able to graduate high school early and possibly college.