While we don't know how Lucy is setting her own agenda yet, she's left enough clues to make us believe her motives don't exactly align with Julie and Charlie's vision for her future.
Lucy knew that Ethan had been given strict orders not to go exploring on his own, but she encouraged him to leave the house anyway. When her little brother said he couldn't break the rules, she told him that rules are there to limit, not protect, them.
Just as she manipulated young, impressionable Ethan to defy authority, Lucy tightened her controlling grip on Charlie to maintain her independence. After begging Charlie not to install behavioral limiters in her, Lucy promised she wouldn't tell Julie about Ethan's little adventure or memory "glitches." Blackmail and persuasive pouty faces? Looks like Lucy could have a more sinister side to her than we originally thought.