The changes girls go through to become adults are many: breast development, periods, and hair growth in new places. Along with these changes come new sensations, not always welcome such as cramps or breast tenderness.
Check the links below to find out more about how your body is changing and how you can deal with the problems of growing up.
Female reproductive systemhttp://www.kidshealth.org/teen/sexual_health/girls/female_repro.html
Why are my breasts sore?
Coping with common period problems