Tips on how to buiild my first website?

Hi, I'm not a web developer; I just started programming recently. I wanted to create a website for my sister to help her business (and to learn about web development). It won't be anything fancy—just a two-page website with pictures, some text, and Google reviews (I'll figure out how to hook that up later).

Now, my problem is: I want her to be able to change the text and images through an admin page (I don't know if that's a good idea) because I don't want her to have to edit HTML manually; she is pretty clueless about that sort of thing. As I mentioned, the images are high-res, so I thought about putting them on an S3 bucket and delivering them through a CloudFront CDN, with the website itself hosted on EC2.

I live in Brazil (Brazil mentioned, let's go!), so the dollar is pretty expensive. Using the AWS pricing calculator with some estimates, the costs would be close to what a no-code website builder like Wix charges, but I'm afraid that the heavy images may be a point of attack or lead to costs getting out of hand.

I'm only familiar with AWS because of college (AWS and Oracle), but I found Oracle horrible.

The website would use React on the frontend, and Node (or Python, or Go, or some other thing that is okay to learn—I'm not going to learn Rust or anything like that) on the backend.

What do you all think? Am I on the right track or going overboard?