Bottle nipple sizes

Cece

I'm planning to primarily breastfeed, then breastfeed and pump once she gets a bit older maybe around 6 or 8 weeks. What size nipples should I get? Everything I have is slow flow, I accidentally got one that's medium flow and not sure if I should return it. I don't want any nipple confusion down the line, is it best to stick with a slow flow nipple throughout our whole breastfeeding journey?