Answer:
Adolescence
Step-by-step explanation:
Annie is most likely to be in her adolescence stage of developmental.
The adolescence stage of developments starts from the age of ten to thirteen.
In the adolescent stage of development, a child grows faster and quickly, changes in body parts arises like the growth of hair in underarms, etc.
The changes in the body can lead a child to be anxious and curious specifically if the child does not know what is considered to be normal as in the case of 'Annie' in the question above.
Adolescents usually have concrete thinking, and need for privacy and find ways to be independent.