Don’t obsess over cup size. In Australia, there is no standardised bra sizing, and what you fit in one brand or store, you may not fit in another. So you will not be recommended or guaranteed a cup size.
You will be recommended a volume that is proportionate to your body, taking into consideration your desired outcome.
Following surgery you may feel that your breasts are now too large. This is generally due to you not having had breast volume, and once you recover and grow used to the size, you may then feel that they are too small!
You can discuss all of these factors with your surgeon; specifically what you desire and what is possible, and then meeting somewhere in between.