tripleS) A group where you can't sense the age difference

How is Yoon Seo-yeon one year younger than Park Saem?
I can't believe Mayu is the second oldest out of 24 members..
Gong Yu-bin and Jeong Ha-yeon are two years apart, but they just seem like friends; Yubin is so friendly that she doesn't really care about seniority.
Even though there's a one-year age gap, Ju-bin treats Seo-a like a baby.
Yeon-ji, who feels like the eternal maknae, is becoming an adult soon and there are still two more members younger than her; it feels awkward to even call her unnie.