Late Period

So the very first time i got my period was last July 1st. Then I got it August 1st. Then no period until November 3rd. Then December 3rd. Then I got it January 3rd. It said I was supposed to get it the 3rd, but it’s two days late. I usually have cramps the day before but I only had little ones this time. I did have a massive migraine on the 2nd though. I wouldn’t be worrying except they’ve been pretty consistent so I’m not sure what this can be caused by. (Btw there’s no possible way I can be pregnant because I’m only 16- I don’t do that stuff) Please no negative comments!! Thanks for your help!