Is it impossible to become music composer?
With about two years of music classes -assuming you currently have no musical training- you could be composing. Musical composition is governed by a lot of rules. When John Williams writes a piece, he follows certain rules of structure, harmony, etc. A musical composition draws out all the material within a musical idea. Coming up with musical ideas is the hard part. Turning them in to symphonies, sonatas, operas, and so forth is the easy part. Whether or not you’d be any good as a composer or make any money is another matter, probably governed by luck more than anything else. Still, you should compose because it would make you happy, not because you think it would be lucrative or you’d sell albums. Most people aren’t Haydn-quality composers- and there’s nothing wrong with that. Anyone can learn to compose or to play an instrument. Nobody can say if you’ll be the next Argerich or Shostakovich, but you can’t lose much by trying.