I had inverted nipples most the time before DS1 and he breastfed like a bloody champ. I rarely got inverted nipples once he was done with me but I still have flat nipples. DS2 had attachment issuesbut I think that was also due to PND so I didn't want to feed him. I expressed heaps and topped him up with that and got the swing of things as time went on and bf till 18mo. I'm hoping to make it till 2 this time. dDS1 only bf till 10.5mo but that was on his own accord. Definitely possible to feed with different nipples, we are all different