Giving pacifier to 4 day old baby...

My baby has been a champ at latching since she came out on Sunday. I'm exclusively breastfeeding (no pumping) and I've realized that she also uses my nipples for soothing. I caved today and gave her a pacifier and now I feel like a horrible mother. Am I setting myself up for failure by giving her a pacifier, and is it okay to have her fall asleep with a pacifier in her mouth?