550cc Natrelle SRX too big for me?

Dear Rebecca.The size your doctor recommended seems pretty big to me. A recommendation like this should be based on your measurements is the breasts with your goals for size in mind. However, breast cup size is a very personal choice and if you’re still not sure about it, you should see your plastic surgeon again to be sure this is the best size for you. 
I have my patients return to the office as many times as they want to resize or try on sizers until they’re 100% sure. We use a specially designed breast implant sizing system which allows to better see into the future. 
As far as expectations, your surgeon is always the best resource for this, but based on your photos, I believe you should have a similar result to your hope photos. Everyone is different, but you look to be a good candidate for breast implants. Tear drop breast implants are probably a good choice for big but not huge upper pole. 
I wish you the best on your upcoming journey with breast implants!Dr. Aldo

I understand your concerns given the size of implant that has been chosen for your surgery. Even without looking at your pictures and knowing your measurements this size implant will tend to given the breast excessive fullness or roundness. Additionally, the SRX profile has the most projection. There are not many breast implants larger than the 550cc implant available so if your wanting to avoid the "porn star" look I would recommend revisiting this with your surgeon and ask for an explanation on why this implant has been chosen for you. Good Luck.