I'm a web developper with 10 years of experience (started front end, now full stack). Web design is just... design, and development is you make things work with code. Making a website from scratch is a BIG job, an e-commerce is 3x more job if not more. If you don't know what you're doing, you're gonna hit a wall real fast. There's a fucking lot of things to take in consideration in a website that if you're not in the domain you don't even know exist. I highly recommend you to start with a website builder. Shopify is great tbh, you start with a base and you can edit it to your liking. Learn HTML and CSS and go from there.

If you have other questions or want more details feel free to pm me.