Hi, I understand your concern, at your age, the stress, hormonal imbalance and pcos are the major causes of your period delay. Once in a year if it's happening, then you need not take it so serious. But if it is happening regularly, and if you notice any symptoms of pain or weight gain or loss it's better to check for
thyroid levels once to rule out the hormonal issues.
Next Steps
do exercise regularly, have plenty of water. Practice Yoga and meditation to reduce stress.