OH SORRY I never thought of putting the SPOILER tag before it bc it's just my assumption ( ̄∇ ̄") oh well. Thanks for pointing that out.
SPOILER:
I think not in her first life but her current life, bc even tho she doesn't remember her past life she mentioned that it always happens,
that every time she reincarnates she wouldn't remember her life before the current one, but remembers all the other lives she lived when she reincarnated, tho she'll eventually remember it after quite some time.
And I think she really is the Princess in her current life, and maybe I thought that the Princess ran away, lived in the slums, drank beer which made her hair dark then passed out? on the street.
OR
MAYBE Lucien was already reincarnated at birth as the Princess and same thing happened she ran away, drank beer which made her hair dark, then passed out on the street which made her forget her memories since childhood, and thought she reincarnated right there on the street.
And it wouldn't make sense if she's the princess in her past life coz wouldn't that change her Physicality after being reincarnated in a different body? even tho she unconsciously remembers habits, retains talents like playing instruments, and her way of talking, you can't really pass your allergy in a different body just because you're allergic to something in your past life?
What if someone says that "maybe Lucien's body is the princess' body?" then wouldn't that be confusing coz she's the princess in her past life then died then came back to her own body??
aaaaaand it also doesn't add up if she's the Princess in her past life coz wouldn't that be like she reincarnated in the same timeline? and same body?? like what you die for if you're just gonna come back to the same place same time same body right??
So my final conclusion is Lucien is the Princess in her CURRENT life, maybe there's something that we're missing and she just lost her memories of being the Princess. I maybe wrong but those other theories above wouldn't make any sense than my conclusion here.
I KNEW IT!!! They purposely brought cookies that contains something the "real princess Luciencia" is allergic to, so when the fake princess does not react to it after eating, that just proves to them that she's fake. But then we have Lucien here trying out the cookies ╮( ̄▽ ̄)╭ and since she's the real princess she's allergic to it. Not sure if I'm spot on, but I'm guessing that's the reason why the marquis and felix got surprised coz Lucien reacted to something the Real Princess is allergic too.