There are several variables in determining implant size. When recommending implant size for my patients, I consider the followings: 1) patients' anatomy (height, weight, chest width, chest height, amount of breast tissue) and 2) patients' desired look/goal. Without knowing your chest measurement and breast tissue amount, I cannot give you any recommendation. You should visit with board-certified plastic surgeon who will examine you. Try implant sizers to get a rough estimate of the size you may want. As you know, bra/cup size will vary depending on the brand. Good luck with you.
Without a proper exam, it is difficult to suggest what implant would be best for you. You also did not state about what volume you would want.