Title: 4/10
This here is a title that's unique but only to a certain extent; I've seen many other titles that are similar to this one so it didn't really stand out to me however, it is somewhat different in its own way. How it is related to this story is what I'm wondering. Perished nostalgia - does it represent the death of her yearning for the past? Does this mean she's now comfortable with the present? I think not. She seems troubled and her nostalgia is very much alive from how you've portrayed her therefore, I find the title to be rather conflicting and unsuitable especially given the present Aemi.

Plot: 12/35

                1/5: Originality
                Honestly speaking, you seem to be lacking a plot altogether! All we've seen so far is Aemi sleeping around and making everyone feel uncomfortable with her cold looks only to later sadly reminisce about a certain number of days. I’m guessing that she’s numbering the days since she lost a loved one? I will discuss this further in the characterization section but for what you have now, I cannot call this an original plot. This idea has been used many, many times to the point that it's actually mentally tiring to see so I would advise you to incorporate a plot twist or a special something - you may not be able to appeal to readers with originality but you can try to set yourself apart with performance as your selling point. 

                4/10: Believability
                Okay, she sleeps with some random guy, later learns that her parents hired her a tutor and it just so conveniently happens to be that guy from earlier? First of all, if Sehun was qualified enough to be a tutor, I'm not so sure he would've been sleeping around in the first place. Secondly, her parents know of her wild nature so wouldn't they know better than to get her an incredibly handsome tutor whom she would most likely end up spending more time sleeping with than studying with? And thirdly, not everyone is in character all the time. I will go more in-depth about this later.

                2/10: Narration
                I think you have a lot of room for improvement here - your style of writing is rather plain and it's difficult to really grab a strong feeling from it. The biggest issues I had actually were with your diction and syntax. Your word choice was extremely strange and a lot of words you used were incorrectly placed. It came across as though you had first written the chapter in simple language then returned to replace almost every word using a thesaurus and for this reason, your sentences were awkward and didn't flow well.
Your foreword, afterall, was a lot better written - not perfect but better - than the contents of the first chapter so with that in mind, I'd like to encourage you to keep working hard