You might not get much growth. However, it is probably the start of the breast buds. Typically that will make the nipples grow and a spot right behind them may get hard. It is the first step in getting the milk glands going. That occurs before any real growth.
However, it is different in each person's chemistry( the speed and extent that ones body reacts to hormones).
Hope you are good with these changes.
With warmth,
Joanna