The pacing is so slooooooooow ! I'm grateful for the translation you made and I don't know if it's the author's dialogues but sometimes it's really hard to get the flow on discussions. For me some words seems so random.
The revelation at the end ... okay little sister Riko, you had your chance with her and you mess up (we will see if it was to get some D*CKS or if it was the famous break up graduation). Now let your big sister get some pink peaches. She deserve it even if she is a coward.