[XY] Starting a New Game

[Dionysus]

Good afternoon minna 

I just wondered if it is possible to start over my Pokemon Y without deleting my old account. I mean, can I keep it somewhere in my SD card or my computer and will it be playabla again?

Or if I delete it once, will it be deleted forever? ( I completed Pokedex, have some nice shinies and too lazy to build a battle team to battle online) 

Waiting for your answers, thank you