Lol I see you saw my tweet, I roughly heard it in the beginning.. Yeah Sowon is younger than JiU (and SuA). It’s only by some months but since it’s in a different year she would call them unnie, rather than if they were born the same year.
Sowon was born in Dec 7 1995
JiU was born May 17 1994
(SuA was born August 10 1994)
Also you asked for the Gfriend birthdays (if I heard correctly)
In age order from oldest to youngest
Sowon Dec 7 1995 (same year as Siyeon Oct ‘95)
Yerin Aug 19 1996 (same year as Handong Mar ‘96)
Eunha May 30 1997 (same year as Yoohyeon Jan ‘97 and Dami Mar ‘97)
Yuju Oct 4 1997 (^)
SinB Jun 3 1998
Umji Aug 19 1998
Gahyeon is younger than all of Gfriend coming in at Feb 1999.
Edit: just noticed Siyeon is older than Sowon too but only by some months in the same year so no unnie calling for her lol.