What are the risk factors of a 500 cc implant on a smaller frame? (photo)

I am getting 450 cc high profile round gel implants under the muscle inframammary incision. My height is 5'2 and three quarters so I am almost 5'3. Weight 120 pounds. Each breast is 12 inches across. When trying on for size, it may be that the doctor gave me teardrop implants so there wasn't as much fullness on the top as I would have liked so I am tempted to go slightly bigger. I still have to confirm with the office if they did, in fact, give me the wrong shape to try on.