TWICE was supposed to be a 7-member group (Nayeon, Jeongyeon, Sana, Jihyo, Mina, Dahyun, Chaeyoung), but Momo (due to exceptional dancing skills) and Tzuyu (due to exceptional popularity with online voters) were added at the end.
This means that Chaeyoung would have been the maknae.
I love Tzuyu, but I would've been mad as hell if my role as maknae was stolen at the very end, lol, especially since Chaeyoung and Tzuyu only have about a 2-month age gap. 🥲😭