should I buy a bunch of breastfeeding/bottlefeeding supplies?

Sh
Before I know if I can produce milk? I hate to go spend a bunch of money on breastfeeding supplies if it turns out I can't produce anything. I have a medela double electric pump and it came with two bottles. I have to buy nipples and maybe a few more bottles and nipples. Should I go out and buy more stuff, or just wait and see if I can even produce milk? I am 37 weeks.