Ryder here, from the Social Care Team at Shopify. Welcome to our Community, and thanks for posting! I'd be happy to help you ensure that your shop remains private until you're ready to launch.
When you create an account with us, your storefront will be automatically password-protected; however, at some point, you may be prompted to disable your password protection page to make it available to the public. This can only be done if you've already selected a plan and provided your credit card details.
If you haven't disabled the password protection page, you should still see this yellow banner on your Admin > Online store page:
If you don't see it, or if you'd like to make sure that your shop is, in fact, password-protected, go to Online store > Preferences > Password protect. You can then check off "Enable password" to keep your shop hidden from the public while you continue building.
You can also go to your Theme Editor to view or edit how your password page looks like. The Theme Editor can be accessed by going to Online store > Themes > Customize. Here, you'll want to select "Password page" from the top drop-down menu. It should look something like this:
Does that seem to help you with ensuring that your shop is locked for the time-being? If not, are you able to provide me with more information or screenshots to help me understand what you mean by 'active'?
I hope this helps! I know you're still working on setting up shop right now, so I recommend checking out our handy new Shopify store checklist to make sure you don't miss any important steps. Please let me know if there's anything else I can clarify.