Board Thread:News and Announcements/@comment-27628871-20151218220901/@comment-27502630-20151226183330

Welp, since you guys still aren't convinced, just keep on mind she didn't know about the Crystal Gems (revealed on Marble Madness) and, also, she wasn't created time after the rebellion (as stated on Catch and Release).

So either way, adding her in that episode would blow the plot (they might add other peridots tho).