Why is period 4 days late? used a condom and no malfunctions. plus he did not get to ejaculate so no semen got inside me.

Too soon to tell: Teens can still have pretty big shifts in their hormone levels so some irregularity can happen. This cycle may have more of a cyst which is delaying the signal to bleed. Glad to hear you are taking precautions. Relax - if your period hasn't started in another week take a pregnancy test. If negative wait another week and repeat. If really concerned - visit with your MD.