Haha no worries, like most people say, soon you will be wonder if they'll ever stop breeding.
Just throwing it out there though, with some guppies like the one I have, she didn't get any black until the week before she dropped. Her gravid spot was like a transparent yellow. This was right when you could start to see the fry eyes, and only at an angle for my gup. Because of the color, it was hard to see if she was pregnant at first or just getting fat from being a piggy...she can eat. Also for fry protection, I tied some raffia ribbon in the tank. It worked wonders since I can't get many plants locally.