Definitely agree with you, because it would take a long time to 'graduate'.
However, I like the idea, but maybe a player could leave the league at the moment he or she thinks it is time to start competing in the regular competitions.
For example:
A player has to start in the beginnersleague and has to play there for one full season.
After this year the player has the option to 'graduate' and play in the regular leagues or stay in the league for one more season before going to a regular competition.