This is the age when child Through its social interactions, begin to develop a sense of pride in their accomplishments and abilities. Children who are encouraged and commended by parents and teachers develop a feeling of competence and belief in their skills. Those who receive little or no encouragement from parents, teachers, or peers will doubt their ability to be successful. So give her a lot a lot of positive feed back, recognition and rewards for what ever she does. Invole in frequent interactions with her where and make her feel comfortable in sharing whatever she likes to. Dont over burden her with your high expectations and standards and provide her with situations in which she gets opputunities to mingle nad tlak with people.
Try this and if it does not work consult a clinical psychologist
to understand if she has nay personality limitations, emotional problems or inferiority complex
which prevents her socialization process. You can also get effective remedies