Hey there, @sgerbeau
Bo here from Shopify Support!
Thank you for reaching out regarding this, it is a really great question. You can only remove password protection from your store after you pick a pricing plan. If you pick a plan while you are on a free trial, then you won't be charged any subscription fees until your free trial expires and if you decide to cancel during the trial you will not be charged for the plan. The free trial is meant so that merchants have adequate time to get their store set up and familiarise themselves with the platform. In order to go live you do need to have a card on file.
It is great to hear that you are close to launching! I would highly recommend going through this guide on buyer's trust before going live to make sure you really are ready to debut your business. We also have some great resources such as 50 Ways to Make Your First Sale and The Essential Shopify Store Launch Checklist that you should definitely check out.
All the Best,