I’m 5’5” and 110lbs. My breasts are C cup and I’d really like them to be reduced to an A or AA, would that be possible?

The best way to determine what your breast size should be with respect to your anatomy and give true advice would be a discussion with a board certified plastic surgeon. Not only does proportion depend upon the aesthetic balance of your breasts with your shoulders, waist, hips, and buttocks, but also upon your objectives, lifestyle, soft tissue quality, muscular anatomy, and long-term concerns. A breast reduction also includes a breast lift.
There is also a limit to how small you can go due to tissue that needs to be retained for the nipple/areola to maintain a good blood and sensory nerve supply. A PS cannot guarantee that a breast will be a specific cup size after reduction. Very large breasts rarely are reduced by more than two or three "cup" sizes. I never promise a cup size because bras manufacturers do not follow a standard size.

Unfortunately, you have not provided photographs or told us your bra size. However, if you have painful breasts you may have mastitis and need to be evaluated medically and possibly surgically. If that is not the situation, an alternative is a lift using The Bellesoma Method. This will reshape your breast tissue creating upper pole fullness without implants, elevate them higher on the chest wall and more medial to increase your cleavage. Vertical scars are avoided, nipple sensation (in 95%) and the ability to breast feed are maintained.

Best Wishes,

Gary Horndeski, M.D.