I had sex on new year aftervthst I got my menstrual cycle on time. Now in march I missed my period. What is it? Could it be possible to be pregnant like this?

When you say "missed" how late is it ?

Did you have your January and Feb. periods ?

Most likely you just late or you are just missing a period.

If you had sex on Jan 1st or near then, you would or have missed Jan and Feb period also.

After you are 14 days late, you can take a pregnancy test first thing in morning, with first urine of the day