I had sex for the first time the day i was supposed to start my period. it's been 8 days and i still do not have it. am i pregnant?

Possible: If your period is always regular and now it is late for 8 days - yes, it is possible.You need to get a pregnancy test. Abstinence if possible. If you continue to be sexually active-need to practice safe & protected sex. You are very young, you want to pursue your dream and your future etc. Be wise&responsible, your world will be completely changed if you get pregnant & have a child at your age.