Ok so i had my first time about a month and 2-3 weeks ago. i had my normal period about a week after but now im late and worried..could i be pregnant?

Sex causes pregnancy: But, it can be hard to tell if a woman is pregnant because some of the symptoms seen in early pregnancy can also happen in non-pregnant women. A urine pregnancy test gives a reliable result if done correctly. One can test about 3 weeks after sex (3 weeks after when conception might have occurred), or 1 week after missing a period.