Apparently there's a 4th edition coming, but if you like the form-factor of a book-length text I'd throw a recommendation to "Database Design for Mere Mortals"[1]. I read the 1st edition from the late 90's, but I'd imagine it's still just as good. It approaches database modeling from a practical non-technical perspective, and I found it helped me learn data modeling in a software-agnostic manner, and later to influence how I talked to non-technical audiences about data modeling. I'm really glad to have found it early in my career.

I will echo what others have said. Data modeling is a force-multiplier type of skill. Combine it with a reasonable understanding of SQL and you can return a lot of value very quickly.

[1] https://www.amazon.com/Database-Design-Mere-Mortals-Hands/dp...