Can you tell me how to know when your period is coming?

Menarche: Menarche usually occurs between ages 11 ; 13 in the us. However for some their period could start as early as age 9 ; for others not until 16. Before you have a period, you will have noticed breast development, pubic hair ; white to yellowish vaginal discharge. Before the first period a girl may feel bloated, develop cramps in legs or abdomen ; feel moody (depressed or anxious).