What size breast should I get at the Plastic Surgeon?

I am going to travel in 3 days to see a surgeon to get a breast augmentation. I am 20-years-old, I'm 5'5 120 lbs, and currently a B cup. I am thinking of going to a full D cup, but I'm unsure of the CCs and how to figure out what size boobs I really want. Also if anyone has any questions I should ask the doctor that would be very much appreciated. Thanks :)