Now in theory I could sell off cards and just join/quit games over and over all in the name of being a "rookie" but honestly that's dumb. The rules are way too restrictive for any active player as you can break past any one of them on your first day following your guides on how to become rich...there are forums that encourage people to grind and what decks to use, there are people with dedicated farms for farming rares... yet your rules create an environment for a PvP event where people are unable to play the game and in any way advance themselves to at some point become productive members of the game.
You should have applied through the regular auction. A total of 84 players were picked that way.
Rookies are 12 players that were a last minute addition to both give newbies a chance to join the War as well, and to see if teams can train their newbie to be a pro during War.
You have tons of cards and score. I don't see how you would be considered a newbie.
Rule clarification:
After being listed as a confirmed Rookie, you don't have to meet the Rookie requirements anymore. This means that you can start grinding as much as you want, and you would still be the Rookie regardless of how many cards you have or what your score is.