Friday 13

Today is Friday 13.This morning before I left my aunt house, my cousin said to me ,"cousin today you have to becareful in anything you do ". I asked him why ?I'm always careful. He replied ," that today is Friday 13 and that mean bad luck for everybody".I would like to know the origine of that, and why is bad luck.I really don't have no idea.If it's true I hope nothing bad will happen to anyone.In my country we don't have any date which is consider good or bad.Have a good day and be careful in what you are doing.