how can i become a real theoretical physicist

I'm not a real theoretical physicist yet, but I can share something I've learned. Firstly, if you want to study physics, you'll need to improve your English, or at least learn how to use a translator properly. That might sound mean, but it's a fact. Secondly, if you're 17, you're still years away from learning QFT. Yes, it's interesting, but start slowly and build up your knowledge from school level through university to working on topics that world-leading scientists struggle with. You have all the time in the world, but the most important thing is to be consistent and not to give up if you don't understand something right away.

The other comment is correct.

1. English is the language of physics, for better or for worse, so work on that.

2. Follow your standard education. Complete high school. Enter a bachelors program and major in physics. After that enter a graduate program in physics. It is at that stage that you will learn QFT.

3. After you finish your coursework in graduate school, you will begin research.

There are many steps after that too, but for now focus on the steps in front of you. Trying to jump the line and go right to things like QFT without learning all the intermediate steps does not work. Once you're in your bachelors, I'd recommend discussing career development with the faculty there and they can give you more specific pointers tailored towards your location and your particular interests.