Did you think that kirino was a girl

no but yes

Yes, I would never had realized that he is a guy if I haven't seen people using "he/him/his" for kirino ._.

LOL its hard to believe he's a he instead of she but yeah i did think of him as a her in start but his way of talking makes me realize he is a he not a she then i notice people calling him he confirms my suspicions

Nope. He is not a boy, He just look like a girl

Kirino is a feminine boy... It means kirino like a girl but he
Is really a boy...