Most of the people that appears as a game counterpart don't normally appear as an anime counterpart (maybe a manga, but not anime)
Due to how many characters are in the game, and not in the anime there's a good chance Serena won't be in there.
Plus, the X&Y Anime has been announced to be a copy of the Kanto anime, so I don't think so. (Is this just my imagination, or was it actually announced? Either way, I come to the same conclusion)
Hope I helped. :)