好きだった年下幼馴染が誰とでも寝ている件

Aika, a girl who is living next door to me
Since our families are in a good relationship, we grew up like brother and sister
Aika is cheerful, cute, and kind to everyone
but she is mean to me, maybe it is because we are like family
But I can't see her as a family member
Because I started to like her as a girl