During the first year of your child's life, she will go from a naive newborn who has little motor control to an on-the-verge-of-toddling baby. This first stage of child development includes rapid physical growth that supports her new abilities. Major milestones include rolling over at roughly 4 to 6 months, sitting up unassisted by 6 months old and crawling or even walking by 12 months. By the end of the infant stage, children also have the fine motor, or hand, skills to use a pincer grasp, pick up and put down small objects and make attempts to scribble with a crayon or other writing tool. You will also notice, as your child reaches between 4 and 6 months, that she will begin to purposefully babble and laugh or squeal with emotion. By 12 months old, an infant may also have the ability to say simple words, such as "mama," and understand a limited vocabulary of basics, such as "no."Adolescence
The teen years mark the a major departure in development, as the child begins to look and act more like an adult than a little kid. During the beginning of adolescence, children will go through a set of physical changes known as puberty. This includes the onset on menstruation, developing body hair and -- in boys -- a voice change. Teens typically strive to become more independent and often focus more on friendships and romantic relationships than those with their immediate family. Additionally, adolescents may look toward their adult futures and investigate a potential profession through internships or after-school jobs.