Socialization is important for children because it teaches them how to interact, talk, read and write and how to tell right from wrong. All of the lessons that children learn through socialization before they enter school is limited to family, family friends and possibly religious centers. These lessons are biased towards this close circle of influences and their preferences on world views.
Socialization skills do not cease to grow or change as a child gets older and heads to school. Their circle expands and so does their influence. They will learn the difference between success at home and success out in the world, that there are different rules for different places and that they are expected to act differently at various places. These skills help them learn to adapt and develop their own ideals about the life and the world.