I’m 15 years old, and my FIDE rating is 1674. I’ve been playing chess since I was one and half years old. If I train, say, something like 15 hours a day and play in 20 tournaments, is it possbile for me to become a 2100+ rated player in 2 years?
To predict someone's progress is very difficult. It depends on so many things: "chess talent", how you practice and train, opportunities to play tournaments (not too weak, not too strong), etc...
Maybe this blog can give you some information, ideas and tips. Of course, your situation is different, for instance, you are 10 years younger than the author of the blog.
Yes, it is possible.
However, you will see from the comments that no one thinks you should bother trying. Why do you think that is? What does your FIDE Candidate Master rating get you? Clearly, everyone should have hobbies and goals, but they should be realistic and well balanced. If you spent all your time playing chess instead of going to school, you will have a great chess rating, but be virtually unemployable. There is little money in the chess industry, either from tournaments or from tutoring.
I stand behind your goal of attaining a Master rating, as probably most users do. Just don't sacrifice your social life, your education, or your health to make it happen.
Here's a great article on chess progress. The higher your rating, the more difficult it is to progress.