I am 15 and my period is 6 days late, is something wrong?

[idkwhattoputsoheyy]

I am a virgin so I don't think I could be present but I don't know if any medical stuff could be wrong. My period usually came really early like this year my periods were like 14 to18 days apart. Then they got sort of normal again, like 20 to 21 days apart. But now my period is 6 days late from those numbers. Is it just my period evening out or something? I have a period calendar that tells me when my period is suppose to come. My last period stated on the 13th of September and its the 14th of October so i don't know if I should be worried. I told my mom about how my periods have been early but I didn't tell her about how this one is late yet because I don't want to worry her if nothing is wrong.