Normal varies from person to person.

For me, that's below normal.
For someone else, that might be above normal.

How much does she eat of your milk per feeding and how often? Does she seem content? Does she make the right amount of wet / poopy diapers for her age? Is she gaining well?

With my daughter we started her out with 2 oz bottles. After a month of her seeming content, the pedi said she wasn't gaining enough (only about 6 oz). SHe was still in the normal range, but just gaining slowly. So after that I offered her 3 oz bottles, and I was barely pumping 3.5 oz at the time. Then I started regularly pumping 4 - 5 oz, so we started offering her 4 oz bottles and found that generally she finishes them or most of them, so that's what we give her. We've offered her a 5 oz bottle once or twice, but she never takes more than 4 oz of it.