Trying to get pregnant

Megan

So my boyfriend and I have agreed to start trying for a baby. I'm on birth control. I take the 21 day cycle one. As I stopped taking it sunday. So now my period normally started 3 days after. So im going to start my period Wednesday. I'm going to start prenatals and stuff. When should I start taking them, and what kind/brand do u guys suggest, and how long do you think it might take for the (bc) to be out of my system.