My Anki doesn't respect my first New Cards Step

When I open a new card, and I chose Again after reading it in order to see it in 20mn (because my New Cards steps are set the way that I see a new card 20 minutes after reading it for the first time), it appears instantly. It doesn’t come 20 minutes later !

Please have a look at the 'learn ahead limi’t in the deck options preferences screen.