Awww he's adorable. It's interesting though seeing the contrast between Irae and Kang's situation. For Irae she's trying to face the reality of her future and making the tough choices on what direction to take. On the other hand, Kang can't help but fantasize about possible futures with Irae.
I'm interested to see how things develop. At this point, while she does have affection for him, I don't think Irae would seriously consider Kang as a love interest. She's attracted to the Sunbae, not only because he's kind and handsome, but because he represents a mature and reliable man, which is something I suspect Irae longs for especially since she grew up without her dad. I think rather than appealing to her by showing a mature side, it'll be Kang's earnestness and loyal/persistent affection that will end up impacting Irae. That's just my guess though, I'll just look forward to what the author has in store.