There's a new article posted on the Official Star Wars Blog that reveals just how long plans to actually do the sequel trilogy have been brewing. In the article, the author reveals the following:
Then on June 29, 2012, I found out. I was called into a meeting to discuss, oh, something or other about updating future messaging for Lucasfilm. In order for me to get a better grasp of what that future entailed, my boss just sprang the news on me that, and I quote, “We’re making seven, eight and nine.” He didn’t say Star Wars. He didn’t have to. Why else would those numbers have any relevance?
There's a lot more revealed in the article so I would suggest reading the whole thing, but thought that the above was rather important to share.