You got that right. Also, I know that this manga's supposed to be wholesome fluff, but please permit me in asking the degenerate's query: who has the biggest cup size amongst the three sisters? I'm pretty sure it's Miwa, but again, since this manga is diabetes-levels of cute, we don't really see a lot of sexy fanservice which makes it a bit hard to tell...
Though that last bit will change in future chapters, because there's no way the author/artist is gonna skip out on all the clichés we get with swimsuit episodes.