We introduced our son to his binky at 5 weeks. My cousin said that every single one of her babies has gone home from the hospital with a binky in their mouth, if that makes you feel any better. She said that none of them had trouble nursing, nor with weight gain, nutrition, etc.
My theory about the human pacifier thing is that it's likely a good thing, ingrained into us through millennia of evolution. Maybe babies don't actually know what hunger is; they just know that they have an urge to suck. Maybe through satisfying their urge to suck for comfort, they often find their bellies full, and that's good for them
For what it's worth, my son would try to suck for comfort and then spit out the nipple when milk came out or simply fall asleep, sometimes with milk pouring out of his mouth
Then he'd have other times when he ate voraciously. When we finally gave him a binky, it was like his dream came true. He was so happy to have something he could suck on that didn't leak milk!
If your little one is not spitting your nipple out as soon as milk flows, then I'd be inclined to say that she actually wants milk, not just to suck, and that she's not just using you as a pacifier, but is just really hungry? For newborns it really isn't uncommon for them to be on the boob almost constantly!