This might be a silly question, or im just not thinking with my head on...but

How do you know when to predict when AF will arrive each month after having a baby...??

Like from when do u start counting 28 days......??

AF not back yet, only been 3 weeks since i had Chelsea, but im asking in advance.
How long does it normally take for AF to become regular again??

Planning the future bubs already so need to know these things..LOL