You are 17 and you had sex on 16th March.
Your last period date is 25th Feb.
So you have 4 days missed period.
I advise you to do a pregnancy
test for HCG
Check the result. If positive, further consultation needed.
Period may be delayed due to other causes like taking emergency pill after sex, stress
So need to investigate properly.
But first do the test.
All the best.
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