Pokemon X was my first Pokemon game and it did not get me into the series at all, however I gave it one more shot with Alpha Sapphire and I like the series now, so I would go with Omega Ruby/Alpha Sapphire.
The problem with starting with a newer game; is if you like it you may want to play all the
Others. But they won't be as visually pleasing. So you may never get to experience the old pokemon
Honestly starting with the first (red/blue) would be easier because it has a smaller range of pokemon. Then continuing from there. Makes it easier to memorize them.
X/y ORAS makes you never wanna go back.