First, make sure that you counted your cycle correctly. The first day of bleeding is the first day of your cycle. Count from cycle day 1 until the 28th day. This will give you an estimate of when your period will arrive. It is normal however for your cycle to be anywhere from 21-35 days apart. Besides being pregnant, other factors can play a role in delaying your period. Many girls have irregular periods the first couple of years after starting their period. Stress and anxiety can cause delayed ovulation which in turn would make your period later than usual. Losing or gaining a significant amount of weight can also cause you to miss a period. Other reasons for a late period can include: illness or a new exercise such as running.
If you are having sex, talk to your health care provider about a reliable birth control method that’s right for you.