After watching that flashback and thinking about it, Nodoka met Yuki in her second year in middle school. Nodoka was the same as everyone else bust wise.

They entered their first tournament when they were third year students and Nodoka was still around the same size as the rest of the girls.

Nodoka already had large breasts before beginning the series as a first year in high school.

So that means...she grew those in less than a year. Holy crap, what did her father feed her?

I don't know, but it should be mass-produced and distributed widely.

Eww... boobs...