Star Wars: Everything We Know About George Lucas' Sequel Trilogy
4. Teenagers
In June 2015, as the anticipation for The Force Awakens was building to groundbreaking new heights, Vanity Fair ran a cover story on the movie, and within there had a detail about Lucas' plans that ultimately weren't used.
"[J.J. Abrams] said Lucas’s treatments had centred on very young characters - teenagers, Lucasfilm told me - which might have struck Disney executives as veering too close for comfort to The Phantom Menace and its 9-year-old Anakin Skywalker and 14-year-old Queen Amidala."
Lucasfilm President Kathleen Kennedy admits in the story that they deviated from the plans in certain ways, and obviously this was one of them. The heroes are still relatively young, with Rey 19-years-old (so technically still a teenager), but the other heroes are all in their 20s and 30s, much like in the Original Trilogy, rather than the story being centred around a bunch of 15-year-olds.