I do not have Pokemon X and Y yet, so I'm doing as much research on Pokemon ahead of time. That was when I read about Super Training. So I wanted to know when can you Super Train. That way, I can keep my stater from unwanted EVs until I receive the feature.
As soon as your given your first Pokemon e.g. your startet you can begin super training! :) Then you will be given a tutorial on how to train your Pokemon in different stats and explains different kind of training bags you get (You'll learn about training bags when you get them). So in short you can have a fully Ev Trained starter before your first battle.
Serebii has some more information
Hope I helped :)
The first time the player accesses Super Training, they are shown a video and taken through two tutorials demonstrating how to use Super Training Regimens (against a virtual Scatterbug and Spewpa) to increase a Pokémon's stats, and how to use training bags in the Core Training screen to do the same.
-Bulbapedia
You can start before reaching the first pokecenter.
