i went to the bathroom and i had brown mark on my underwear what does that mean is it normal?

ANDY'S ANSWER: Yes, it's normal and that could very well be a start of a period. Blood turns brownish colour when it's older or dried. You could start by wearing just a pantiliner if it just a mark on your underwear. That will keep it from staining. Later, if you start getting a heavier flow, you can change to an actual pad, or even tampons.