Breastfeeding Supplements before giving birth?


I figured I would post here, instead of in First Time Moms because several women here can give me experienced advice.

So, I REALLY want to be able to exclusively breast feed when my son is born, and my cousin gave me all of her breast feeding supplies, because she wasn't able to use them. However I am only 23 weeks pregnant. I thought about starting the supplements now, just to be "safe", but I dont want to mess whatever flow I have now up.

Any advice would be GREATLY appreciated!!