So on my 3DS clock, it shows that it is now the 24th of February and I have already completed the days work for the 23rd. However when I load up the game, it still shows that it is the 23rd. Any help?

i'd like to comment but first of all disclaimer-- i do have a bad knowledge regarding GMT or time differences...

i tried playing the training modes at night yesterday, and until 12midnight i'm still up and playing the game (relaxation mode), though after a couple of minutes (00:30) it doesn't let me play the training modes even if it's already 00:30 on my 3ds clock.... though when i woke up at 11am, it let me do the training again...

so maybe there's a minimum hours of cooldown or it just let you train your brain starting breakfast time.... XD i'm not that sure...

True... it let me play again today just now...
Maybe it starts up sometime between 4AM-12PM
So that the game actually makes you get some sleep too ;P