About breastfeeding, is there a difference in the flow rate of breastmilk between small aa breasts and regular b or c breasts? do aa's flow slower?

Flow rate: There is no defined or discovered flow rate difference based on breast size that i'm aware of.

No!: Breast size does not impact milk flow or volume. In the newborn period follow your baby's weight often to be sure adequate milk supply is allowing normal growth. Babies grow 1/2 -1 ounce a day the first few months (after the first week's weight loss!).