No amount of just passively watching anime will teach you a language, especially when you're just reading subtitles in your own language. Your brain is not paying attention to the target language, you're just paying attention to your native language.

To actually start learning, you need to do real study. Textbooks, lessons, spaced repetition, graded readers, etc.

Once you've learned a good amount of vocab and at least a little bit of grammar, you'll have to take the plunge into immersing yourself in native content.

But here's the catch: you will not be comfortable the first time you try to watch something without subtitles. If you keep putting this step off until you think you're ready, you'll never actually be ready.

The first time you start immersing, you're barely going to pick out a few vocab words, but you're not going to parse a full sentence, let alone follow along with the story. And it's going to feel overwhelming and frustrating.

But that's the grind you gotta push through. Little by little, the bits and pieces you pick out will add up. Ideally you should even be taking notes as you do it, looking up new words and making flashcards. Immersion learning is homework, and you have to really work at it. The trick is that you're not just watching passively, you're studying actively.

You'll never get to a level where you'll feel comfortable until you've spent a lot of time feeling uncomfortable first.