Back on birth control

First month back on birth control after having our second baby and being off birth control for almost 3 years! How long does it take to be effective? I started it at 6 weeks postpartum, pp bleeding stopped a week beforehand and did not have a period during that that time. Currently just starting my 2nd week and have had some of the normal spotting while body gets back into a groove. Some sites say it’s effective after 7 days, some day a month.

We are DONE having babies so avoiding any surprises with the pill until we look into something more permanent.