Yes you can! Just do, do, do, learn, learn, learn. Browse the internet. When you find something interesting, open dev tools and find out how it's built. Try to remake it yourself. Read books, Hashnode, Reddit, Hacker News. Follow Dribbble, Designer News, Behance, FWA. Ask from more experienced learners. Use Google.
Always think about how could details be even better. Think about the user, be critical. When you see products out there, think about how they could be better. How would you remake them?
Build node gardens (https://nodegarden.js.org), Deck of Cards (https://deck-of-cards.js.org), minesweeper (https://bombsweeper.js.org), view libraries (https://redom.js.org, https://frzr.js.org), state handling tests (https://pakastin.github.io/redom-state) or whatever pops in to your mind. Even if it's really far away from what you would think about doing as a paid job, you always learn something new or some fresh point of view.
I have never officially studied anything related to my work in my life, except some basics of c++ in university of technology which I dropped out from. I haven't ever needed c++ after that.
I am a fullstack JavaScript developer + designer. I started in 1999 playing with Flash 4, creating animations when I was 14 years old. Gradually I just learned to code without even thinking that much about it.
Designing is something you learn by always thinking about minimalism and harmony, and pushing your work towards those. And copying from others, taking things here and there. Building your scrapbook of the best UI you can find and mixing them until you find something unique and beautiful.
We all start from zero and I tell you, they don't teach you everything at school. Most of the magic you just have to learn step by step. Work by work. Fiddle after fiddle. Sketch by sketch. Design after design. Code of line after another.
Good luck! 😉