Mano Erina - 51 -
Her birthday is 4/11, and 4 + 1 = 5 & 1 = 51. Maybe.
Translations of the shirts:
Sayumi: Angel cat
Reina: I love Tanaka Reina
Mizuki: Are you having fun?
Erina: It's forbidden to
oshi hen* from Ikuta Erina!
Kanon: I ♡ Morning Musume。. Please take care of Suzuki Kanon.
Ayumi: [I can't read it.]
Masaki: HAPPY 10th gen member Masaki~ Yeah Yeah Yeah~
Haruka: 10th gen Haruka LOVE
*Oshi hen = change
oshi (favourite member). So, for example, removing Eripon from your #1 spot and putting Haruka there.
Chinami: Eternal middle school student!
Airi: Even if you give an excuse... it's still an excuse? (lol)
Mano: I'm a Manofriend... so what?
Ayaka: I'm the leader of the idol group with the shortest skirts in all of Japan!
Kanon: Cindrella revolution [something]... please!
Kana: I really love!! Osaka
Some of these are probably wrong
.