Title:
The title is a mouth full, really. I personally think the title is too long and is too generic. I've seen titles called "Loving you was my favorite mistake" before or even titles that are similar to it so it's not a title I'd click on if I saw it roaming around the website. It's not really original per say and I think there could have been a better title for it if thought about harder (though I know how difficult titles are).

Description/Foreword:
The description is too spread out(?) to put it that way. The description can literally be put into a sentence or ...a few instead of being every line. Like: "Mistakes are known to be doing something wrong. She was an orphan, she was alone and she was longing to love and be loved. She did a mistake which gave her a family and love, which she longed for years.

The perception of Mistake was completely wrong in her life but what if one day the mistake she did threatend her back to take away the Family and Love she got? Will her Love overcome the mistake? or the mistake punish her Love?" 

That  looks more neat instead of scattered but then there's the second issue: the capitalization and some of the awkward grammar. Some things that shouldn't be are in caps while things that should be capslocked are not. Also, the excessive use of periods is a bit too much. 

So all fixed it would be something like this (changes are in red): 
"Mistakes are known to be doing something wrong. She was an orphan, she was alone and she was longing to love and be loved. She made a mistake which gave her the family and love she always longed for.

Her perception of a mistake was completely wrong in her life, but what if one day the mistake she did years back threatened to take away the family and love she got? Will her love overcome the mistake or will the mistake punish her love?" 

I changed a few things to make it sound better and I fixed the weird capslocking and misspelling of "threatened". Also I took out the end part with the whole "chingu" thing since, I mean, it's not really needed. You asked the question, so there's no need to tell people that but that's just my opinion. Also, A/N (author note) stuff should usually go in the foreword (which is what the chingu thing kind of is) because the descriptions are for the story.

Plot:
The plot is pretty cliche, I've seen these kind of fanfictions before where the main characters (usually a girl unless it's boy/boy) is an orphan that's done something they shouldn't have, or something like that, and it's just kind of silly. But overall, the plot is very cliche and doesn't seem that original or exciting. Not only that but the way the two characters met was strange? Like-- what happened to him that didn't hurt the baby? If something like that were to actually happen, I'm pretty sure that baby would be dead considering they are much smaller than an adult male. 

The story was strange, I mean- she longed to be told I love you and here this guy randomly is with a baby and she just met him but is acting as if she's been in love with him for years- it's just strange how fast it went.

Writing Style/Flow:
In all honesty, the writing style could be improved a little. English most likely isn't your first language, which is totally okay, but the writing style is somewhat dull. I think it's because of the excessive use of the periods. When it comes to that, it makes everyone sound dull (if someone is speaking) and the whole story just kind of comes off as dull, too, which is not what you want.

The whole thing is just kind of strange. The way everything is with the periods really does throw it off. When someone talks, you should probably use " " to indicate that because if you don't, it's kind of messy and you kind of can't tell when someone is talking.

As for the flow, the story seems to be going too fast. By the second chapter she practically already says she is attracted to him despite just meeting him.

Characterization:
The characters are a bit everywhere, I guess. I don't know how to really explain it. I feel like you can't really get a good reading on any of the characters. The main character, Shinhye, seems to fall way too easily if she's already attracted to this man. Like Elsa said to Anna "You can't marry a man you just met." but in this case, instead of marry it would be "love". Cause love at first sight is a very rare case.

Personal Enjoyment:
Not my kind of story, it sounded dull due to the periods as I said before and the whole cliche thing isn't my type. Also the pacing was too fast for me as well as how they met, that was just plain strange for me.

Also, since there were too many chapters for me to read, I only skimmed a few.