"Testing the waters" before legally registering a business? : shopify

Hi guys,

I'm an Italian boy, and I'm 18.

I would like to build a Shopify store because I have a particular business in mind.

By the way I'm really confused about what I should "fiscally" do. I mean I feel too beginner to open a fiscal position and I would like to test the store before of opening a fiscal position.

I would like to start without a VAT number etc. and then if the store works I eventually register my business.

Any expert advices on what I could do?

P.S. The business I've thought, consists of selling digital products (without a specific geographic target, I can sell them all around the world). The products I sell, by the way, have copyright, but the way I handle this aspect is by buying the rights for commercial use from the owners, by making them sign a contract, so they give me the permission to sell their products on my store.