Birth Control Probs

Katie • hi im katie and i like pokemon and cute things
So I started my birth control pill on the 21st of August and I just got what I think is my period today. It's wicked light and looks like fresh blood, unlike this weird brown discharge that I've been getting (according to other girls it's normal, it's just old blood) I wanted to know if that brown discharge will come every month? And is it a bad thing? Also, how do I know if this is really my period or not?