Hello tuhina; welcome to HealthcareMagic The normal time for start of periods can be anywhere from 11-16 yrs and 13 yrs is an average.So at 14 you are still not late.The reason for the delay in some girls can be -Variation of normal or constitutional delay -prolonged high level of physical exertion, e.g. from being an athlete -Systemic disease like Inflammatory bowel disease, chronic renal failure anorexia nervosa, zinc deficiency. Hypothalamic defects and diseases like Kallmann syndrome - hypopituitarism gonadal defects and diseases like Turner syndrome, Klinefelter syndrome ;Ovarian failure -Other hormone deficiencies and imbalances hypothyroidism Presently no reason to get worried but if you don t get by another year you need to consult a Gynaec and get investigated and if needed treated. Thanks