I'm 4'11, 92lbs, 12 BWD. Is 210 Cc Moderate Enough to Achieve a Full B Cup from an AA Cup?

Unfortunately, you have not told us your bra size just your cup size.  If you are a 32 or 34 each 100 cc's of implant corresponds to 1 cup size change.  If you are a 36 or 38 each 200 cc's of implant corresponds to 1 cup size change.  From this, you can calculate the size implant you will need to achieve your desired result.  Silicone gel implants placed retro-pectoral look and feel more natural and are less likely to ripple.

Best Wishes,

Gary Horndeski, M.D.

Thank you for your question. While this is a question best answered by your surgeon after having examined you, in general the difference between the two sizes that you mentioned are very small. I would recommend having a discussion with your board certified plastic surgeon again and undergoing Vectra 3-D imaging for you to visualize postoperative changes between those two implants. I find this extremely helpful for patients to visualize the size and shape of their breasts with proposals of different size and shape implants. 

Depending on your goals and objectives, either 210 cc or 240 cc are reasonable options. The size of the implants are based on a combination of a patient's goals
and objectives and her anatomy. In order to provide a natural looking
augmentation, the surgeon needs to evaluate many factors including soft
tissue coverage, skin laxity, chest wall width, breast imprint width,
the shape of the breasts and relative level of constriction to ensure
that the breast implants are appropriate for your body. Consult in
person with 3 experienced and expert board certified plastic surgeons to
understand your options.

In order to make an accurate size recommendation, I would need to assess your chest wall and breast mound measurements and characteristics.  Unfortunately, there is not a general rule of thumb or objective criteria to implant selection.
Your plastic surgeon will perform several measurements of your chest wall and breast anatomy and determine a range of implants that both fit your chest wall and reach your desired goals.
The next step is to try on this range of implants in the office with your doctor.   The key to this success is showing your surgeon the body proportion you desire with a bra sizer and allowing your surgeon to guide you to the right implant.   It will be much easier to communicate in implant cc's than cup size when determining the appropriate implant for you.
I wish you a safe recovery and fantastic result.
Dr. Gill

the difference between the two sizes you are contemplating is significant only because of the smaller original size of your breasts and chest. proper sizing can only be performed with an examination and measurements