Via oc-growth-and-development

If you have twin OCs, which one makes a bigger deal out of being the older/younger twin and which one points out that it doesn’t matter cause they’re twins?

(sims4 screenshot edits)

Anelaire, "Elaire", the eldest. Very much "I'm the eldest." Very much doesn't want anybody thinking she's Piri. Very much in the belief that being eldest is a defining factor in her as a person (despite the fact that her mother, who is in line for the throne ahead of her, is NOT the eldest, and her grandmother, the Empress, could easily abolish the hereditary monarchy well before it'd matter anyway)
Pirimme, "Piri" actually doesn't care, in the sense that she doesn't make a big deal about it, she knows everyone knows she's not the one in line for the throne. However, in that sense, she does care, because not being her sister... or maybe because her sister is Elaire, means Piri doesn't worry about stepping into that role, for better or worse. 
The weight of how much they each feel their birth order matters, means they probably aren't either going to say "it doesn't matter"... rather its everybody else in their lives who give them grief when they bring it up.