It is not normal for your period to be 10 days early. Most women have a menstrual cycle of 28-30 days. As long as the cycle is relatively regular and fixed, it is a normal menstrual cycle if it is advanced or postponed by less than 1 week. However, if the menstrual cycle is less than 21 days, the menstrual cycle is too short, usually due to endocrine disorders of the ovaries. If the menstrual cycle is 10 days early, it is obvious that the cycle is too short. If the menstrual cycle is early only once in a while, it may be due to a transient disorder of the ovarian endocrine function caused by poor living or eating habits, environmental factors, stress, etc. If the menstrual cycle is 10 days early every time or if this happens frequently, it is considered to be a serious endocrine disorder and needs to be properly checked and regulated.