This is an accepted solution.
Hyde here from Shopify.
While it is possible to hide your store by way of a password page, it is not possible to completely remove it from the internet because it lives on the internet! Digital stores are not unlike real stores, they remain boarded up until they're ready to open their doors, but they cannot disappear completely.
Unless someone is specifically looking for your store they're not likely to find it online anyway. And besides, part of successfully launching a store is in successfully leveraging the feeling of anticipation by letting people know something is about to open.
Here are some pointers on preparing to launch your store, and here is how to edit your password page.
I hope that helps, but please do let me know if you have any other questions.
All the best, Hyde.