Help...!!! is this my period?

ok so for the past 6-7 days ive been having like a blackish discharge...not brown or red. its only when i wipe and sometimes i'll see a tiny bit in my undies. it stopped 2 days ago. to me it kinda looks like its fluff from black material but its kind of like normal discharge only black. i havent been wearing anything black near there. i only wear white underwear and normal skinny jeans. so what does this mean? did i just end my first period. i am 12 years old and have had discharge for 6 months. im 100 lbs a 34 A and 5.1ft if this helps. plus im 12 years old