Hello there , If you are sexually active you must rule out pregnancy. if you are not sexually active , delayed period could’ve because if hormonal imbalance or lifestyle changes or stress. As this is happening for the first time with you can wait for periods for 15 days from your expected date of periods. Otherwise you can take prescription medicines for getting periods .
Next Steps
Wait for periods. if no periods within 15 days consult a obgyn doctor online or in clinic ( opd)