Are 600 cc implants too big?

I am 24. 5'6'' tall. 127 pounds. 36A. Big ribs. No kids. I tried 500cc at my surgeon's office in a sports bra and I loved the look. My surgeon said he had to add 100cc more to get the same look, which means it would be 600cc. For me 600cc sounds like too much but is this how it usually works? I am looking for a D size don't care about natural look. But 600cc to me sounds too big!