I accidentally opted not to continue Lucias story, is there a way to revert that?
There is no way to start someone's story again once you've ended it unfortunately. Unless you knew how to cheat.
Are you... willing to tell me how to cheat?
You can use a program called Unren to enable the in game console. Once that's enabled you can type in: lucy_friendship = 1. Alternatively, there are cheat codes and such for patrons on Patreon.
Alright, thanks a lot :)