my sister is 16 years old and her periods are highly irregular. the doctor adviced to put her on birth control pills to normalize. I knw that doctors are expert in stuff like this but I worry about the hormones especially since she is only 16.
its always better to solve problems as they come rather than to wait at a alter time. besides, highschool is the time when most people experiment with sex... this is an added bonus. im sure your sister will be responsible.