I agree I think her blushing early on in the manga/anime is only a reaction to Hak's teasing. I've always thought the turning point for her was chapter 64, when they go to Senri Village and she notices that Hak's popular with girls. The next chapter, he makes a move to kiss her but pulls back last second. I don't think she realizes it herself, but she seemed almost a little disappointed that he pulled away. I think that's when she started paying more attention to him.
yes yes and before that it was sealed when she was conscious about sleeping near him in ch 63. things changed and the first to notice was jaeha