What does it mean if my period was a couple days late then when it did come the blood is brown and light?

Probably period: Brown equals old blood. It sounds like that was your period although likely not a normal period for you. It is typical to have an "off" period every now and then. This usually corrects itself over the next few cycles. If it continues see your doctor to discuss cycle regulation. Birth control is very effective at regulating the cycle and preventing pregnancy.