New to breastfeeding

I am currently pregnant and want to breastfeed after I deliver. I am looking for first time suggestions as to what I should start thinking about as far as supplies go. I have inverted nipples and I will have to pump when I return to work. I also know that pumping can help to pull out nipples when inverted. Mine are the highest degree of inversion and I feel that I may have to exclusively pump because of that. I am also curious about flange sizes. What size works best for inverted nipples? I have large breasts 36G currently and they still can get larger. Also what are the must haves that I should put on my registry? Thanks!