Hi, I've recently turned 13 and for four days on and off I've been getting really dark brown discharge in my knickers, it looks kinda like poo but I know it isn't because it smells just like normal discarge, and is in the same place where i discharge normaly falls in my underwear. I've had little cramps but no blood so far. I'm a late developer for my age since I'm still flatchested, I only have breast buds. Even though I'm a late developer for my age could this be a sign my periods on its way?