Before I start writing I want to tell you not to get discouraged by my words, I'm simply pointing out the places you can improve your writing. There is nothing a good edit cannot fix. With that said let's go...
Title :: 2/5
The title matches the story really well and has so much relevance to the starting of the story as well as the theme, but the title is not a unique one and would easily be lost in the many under the same name. There is nothing about the title that either stand-out or piques the reader's curiosity. I would really suggest changing this.
Cover :: 1/5
The cover is doing nothing. It's literally a picture of half of Jimin's face and neck. Honestly, the picture of a cover you have in chapter 18 would look so much better than the one you are currently using. The author's name isn't written at all and the font used to write the title is too small.
The cover needs to be changed if you want to draw in more readers. If you cannot make one yourself (which is completely fine, not everyone can be a designer), you can try at a graphics shop for a good one. Whichever option you choose you really need to better cover.
Blurb :: 5/10
Your blurb isn't unattractive. It gives the reader a synopsis of what the story is about, however it is a literal part of the prologue. And contradicting my earlier point, it isn't giving us much insight to what kind of story we are getting into. I mean sure, the blurb literally tells us that Yerin proposed and was rejected by Jimin, but what about the rest? Maybe an insight of what follows?
The blurb doesn't have to give us the whole point of the story, but it needs to give us an insight of what the reader is going to get into. A little explanation, maybe even a quote from the characters, but overall it needs to give us a basic synopsis of the plot.
First Impression :: 1/10
The cover wasn't really attractive, the blurb, while good, wasn't insightful and the thing I usually judge to read a book the most is the hook. And since we already talked about the previous two, let's focus on the last one.
I'm forgoing the intro and prologue, because in all honesty, the story really starts in chapter one and the prologue is merely there to give insight to the story. In your story's case, I felt that you could have forgone the prologue altogether as most of the insight we get in the prologue happens in chapter one. As I already said, the prologue is supposed to be an insight for something big happening later in the story and not for the very first chapter. A prologue is something people usually forget until the inciting incident happens and then we go "ah so that is what was mentioned in the prologue". I think as writers mostly everyone forgets this and it's not just you doing it.
