I believe she's asking how the hell it is that either Senka or Kanae could have the other as a mother or daughter, but I'm not sure. This is a tough one, even if I could fully understand it, I'm not sure I could word it well in English...
Of the chibi heads in the last panel, Senka's looks most yukkuri-like, what with how it looks like the hair's resting on the ground.
'keayWhat are you on about?Younger sisterNEW! MotherOlder sisterYou're Senka's friend, right?
Lit. Kanae said "You're onee-chan's friend, right?", she's referring to her eldest daughter as "older sister (of Senne)".HuhWelcomeShe's dangerous, so just go over there, mumAnd you know, it's odd.. What is?Please be good friends with Senka, OKSenneSenkaWhich route should I tackle first?