Last Minute Baby Purchases

So I am really pushing to get all my necessities ready to go at least one month before due date. My anxiety and "what-if" scenarios have gone nuts in my head about delivering early, and I want to have peace of mind knowing I have all these things in order- however, hubby seems to think that we should be waiting until after shower to get ready- which is at the 38 week mark (he planned a Independence Day party/shower- so sweet of him to take charge and handle everything, but dear lord I am freaking out over here on timing!) My question is, should I put on my crazy preggo lady pants and demand things to happen my way? Or trust that this will all go smoothly by waiting?