Okay so obviously this being her first acting gig I think puts quite a bit of pressure on her, however, I think she's literally doing a great job. But I also think she has a role that suits her very well.

Her facial expressions match her character but they can be a bit awkward.  Rather than discrediting how well she's doing acting so far I think personally she should stay with these types of roles while feeling out her acting.

I think she did really well I knew her from Singles Inferno 2 and I knew she was gonna be in a drama but completely forgot since they announced the cast first ages ago. I couldn't even tell it was her because of how much she transformed as a character, even her voice is different! She looks way shorter compared to Singles Inferno. I didn't have high expectations when I heard she would be acting but she really impressed me since I watched about 9.5 episodes just thinking she's an actress as her only job 

 EmaraSign:

I think you're thinking of Shin Seulki who plays Doa. 

OP made a mistake with the name, she meant Jang Daah who plays Harin. 

ohhh my bad 😭😭 thank you for letting me know

I though da ah did well but you can tell it's her first role

I  wasn't even aware this was her first role, really enjoyed the way she captured the psychopathy of the character with those gazes and facial expressions in general :}  Will certainly stay in my memory.