I'm sixteen, haven't had sex but im not getting my periods from past 9 days. ?

Amenorrhea: Young girls often do not ovulate every month. Their periods can be delayed if they are exercising too much; they can be delayed if they are not eating enough calories. Stress and fatigue can also play a role.

Late period: Reasons for missed/late periods: low body weight, obesity, marked weight ^ or v, over-exercise, endurance athletics, breast-feeding, ^ stress, illness, eating disorders (bulimia or anorexia), anovulatory cycle (no egg released), travel, hormone irregularities, drug use, meds (i.e., birth control) or medical problems. #1 reason is pregnancy. According to mayo clinic "women who have missed at least.