Board Thread:Naruto Discussions/@comment-2245550-20160501144337/@comment-3965545-20160501193352

Yes but that was supposed to be soon after he joined that Oro left. And he joined Akatsuki right after leaving Konoha according to Hiruzen in the chapter he was brought back again as an Edo in front of the Uchiha Stone Monument. The only mention of Itachi being 13 with any relevance is him becoming Anbu Captain at 13, that's it.