Brief Answer:
Get investigated as advised

Detailed Answer:
hi,
I have gone through your question and and understand your concern.
Delayed periods at this age can be due to stress, hypothyroidism, hyperprolactinemia and poly cystic ovarian syndrome.
You can get a thyroid profile, prolactin level and ultrasound done to confirm the diagnosis and management accordingly.
Another possibility may be pregnancy if sexual intercourse done. Get a urine pregnancy test done in such a scenario.
You should provide more details and any reports if available.
Hope you found the answer helpful.
Regards
Dr Deepti Verma
OBGYN specialist

---