Being a Small A Cup, Will a Moderate Profile, 265cc Silicone Implant Provide a Natural Look for Me?

Generally speaking, the bigger the implants, the higher the risk of complications.  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

Its har to advise you on size without seeing photos.  The most common reason for dissatisfaction after breast augmentation is that size is too small so I would suggest that you have the doctor try different sized implants in your bra to assess size before your surgery.  Scott Newman, MD FACS