There is no set date cheats come out.
Cheats are discovered by hackers such as Smealum, and may or may not be released into the public. It is all up to the hacker's preference.
The 3DS also is much harder to hack than the DS, since it has hack guards and the blue hexagon for a legit Pokemon caught/bred in Kalos in X & Y.
As for now, why don't you play the game without cheats? It's just as fun.