Early stages of brainstorming shopify app idea

[abcpa]

I would like to build an app (or maybe an extension) that allows customers to get discounts on certain items (as specified by the store owner), or have the ability to purchase certain items if they meet a set of conditions. A few API calls will be made and then some logic will determine if the customer is eligible for a discount. The store owner would need to have the ability to specify the discounts and what is eligible for a discount so that the app can apply the discounts to the respective items after the logic is applied.

I know python, javascript, node js, html, css, but am not a developer by any means. There is a lot of info out there and based on the above, I was hoping the community can share with me some tips/info to get started exploring this idea :-). Thanks everyone for the help!