[Kadauz]

MysticLight, if I correctly have understood - you wish to become the "game designer"?
It is one of the main people in development of game. The chiefs of the project.
By main (senior) by the designer you do not become! It is the fact!
And junior... I doubt...

The game designer should know and understand base in:
Programming (more than one programming languages)
Drawing, modeling
Sound, music
Computer technologies
Cinema of industry
etc.

You should be able competently write the scenario.
To be able to supervise over the people (chief).
To be the good psychologist.
It is good to understand game industry.
To know advertising skill, management etc.

You should be the writer, film director, chief, artist, programmer, sychologist, manager... etc.
You have little chance of success...