Is learning Vue.js instead of React a mistake?
It's a problem that happened to me a couple of years ago, and now I saw some people asking the same thing. Vue.js was the first UI framework I learned and it's a fantastic piece of software. But...
There are way more resources to learn React. There are more libraries for React. There are also more job postings requiring React devs rather than Vue devs. And that might bring the question, was it a good idea to learn Vue.js first?
YMMV, but I (and many people) found that learning your first UI framework helps a lot when you have to learn another one. For example, if you already know Vue.js, learning React generally becomes easier.
UI libraries are generally based on the same core concepts: declarative bindings (you link the page contents to the data; when the data changes, the content is updated automatically) and reusable components.
When you learn a UI library for the first time, you also have to learn and get used to those concepts. But once you internalized those concepts, learning a second UI library becomes easier because you only have to learn the new syntax.
In conclusion, there's no reason to worry. Not only learning Vue.js was a great idea, but it also helps you if you want to pivot to another UI library.