It sounds like you have been doing some excellent work on building your store - well done! That is awesome to hear. Have you been enjoying the experience so far? What kind of products are you going to be selling on your store?
I understand that sometimes the 14-day trial may not be enough time to get your store exactly the way you want it. Keep in mind that you don’t have to ‘go live’ with the store after selecting a plan. You can continue to work on the store and only disable your password page when you feel you are ready for customers to see it.
Was it mainly product or theme images that you needed more time with? Just so you know, we have some helpful info about uploading images here.
@AvadaCommerce would be correct in saying that if you do not select a plan and add a payment method before your free trial ends, then the store would enter what is called a frozen state. The only way to re-open the store would be to login, select a plan and then add a payment method.
I would recommend reaching out to our support team using this link here. We can have a closer look at your store, and make sure that you wouldn’t incur any extra charges if you left the store idle in a frozen state, then decided to re-open at a later date. If you explain your situation to us there, we will do our best to accommodate you during this time.
As you are new here, I am recommending the following resources. They are great tools to use when learning about Shopify, and will help you get off to a flying start!