A week into the new school year, you notice your breasts have again began to increase in size again. While they started the year at a good D cup, by the time you're through two weeks, they're already large DD size. Your parents are currently strapped on cash, so you've had to take up seeing you hem your clothes to keep up with your mammoths.
You and James are now dating, and have almost gone all the way several times. Another week, and they're now solid E cups. Another, and they're each near the size of your head. Though you think they're a bit big, you have no choice but to let nature take it's course. Nature, of course being your uncle's doing so many years ago.