I think this story tries to do too much. In covering ground already covered, with words hurried by length, this story leaves me wondering why. What new take did you have on this story that other authors haven't covered? I didn't see it.

There's nothing wrong with covering ground other authors have trod, but some kind of fresh perspective or unexplored relationship can help a new take feel fresh. I'll fall back to a more-technical look at the narrative and prose. Which I'm too tired to examine in detail tonight. Suffice to say that the prose within each scene more or less worked for me. Nothing deeply profound or surprising, but workable. Colorful even.

Between scenes... you lose me on the narrative. There's too much skipping. I don't feel like we settle down into any scene long enough to learn anything really deep or profound, or to provide insight into the characters. The strong central conflict that ties things together is missing.

Through the Mirror:

This feels less like an introspection into Sunset and more of a re-cap of the movie and comic. The new scenes/thoughts that we get are not fleshed out nor do they add to the original story. And some of the page breaks could be combined together, for instance the first three segments after the number 2 (not sure why there are numbers, assuming before and after time skip?) could have been combined into one section, with pillow-facing Sunset thinking about how her getting the crown went mostly to plan but now had a huge hurdle. Over all this story doesn’t bring me any new information than what I would get from having watched the movie or read the comic. And there are a few moments where I was briefly distracted with information.

When Sunset first comes through the portal, I was first distracted on how she lost some enchantments, of which I don’t know what they were as they weren’t mentioned, yet the enchanted journal still worked. Then was distracted as she was first surprised by what she found/didn’t find inside her bag, before the weird digits and new species. I figured the order of those would have been reversed.

I would suggest finding that one element you think the original is missing, and write your story by adding that element.

This piece reminded me of "The Fall of Sunset Shimmer" by Minty Root. It follows awfully close, so I suspect some inspiration came from it.

Like Lofty said, there isn't anything inherently wrong with following a path that many have trod, sometimes, as Tangerine Blast's bio says "Sometimes you just want to hear your favorite story told a little different"

On a personal note, I have a soft spot for Sunset Shimmer, especially with what she goes through post- the first EQG movie. I enjoy this piece for the simple fact that it goes over a common perspective of the character written in different words.

Particularly the part where Principal Celestia comes in takes Sunset to her house is my favorite part. Capitalizing on that will help a lot. I'm a sucker for slice of life and slow scenes where heartfelt moments take place. Good questions to answer would be "What is Celestia's logic in taking Sunset back to her house? Would she be afraid of charges of kidnapping? Why weren't the authorities called to help find her parents? When Sunset mentioned that she is practically an orphan why didn't Celestia express more concern than she previously had? I know Sunset basically said 'don't worry about it' with a mindset of 'I'll overthrow you later' but Celestia would probably pry a little harder since this isn't exactly a situation that happens every day.

Also, with what thisisalongname said about the enchanted tomes losing their power seeming to be an unfinished plot device. Did you mean something deeper than that? Does this make her a little more freaked out since her magical instruments will not work in this world (I think the equivalent is an HIE where a person happens to have their phone, but surprise! It doesn't work. In response, Human freaks out because they are attached to their phone.) Maybe she thinks she is trapped in this universe and she thinks in order to get back, she needs her tomes which are rendered useless in this universe. I don't know what you are going for. There's a lot you can play with here.

I don't know if this is what you want. The reason why I'm going ham on this is because I see a diamond in the rough. A lot of polish, and you've got yourself a gemstone! Also, I would like to see how this turns out if you do decide to polish it!

I have to hand it to you, even if the writing is a bit rough, you've made me an excited puppy. I want more! But altogether, it's your decision.

Thanks for writing!

It does seem as if this is "Sunset Shimmer: This is Your Life!"

Where this shines is when it touches on what we don't already know. The hint about the enchantments that weren't going to work. The accepting of Principal Celestia as an alternate mother figure. These are things we haven't seen about Sunset in canon.

Expand on those, and the other areas where we haven't seen Sunset -- maybe what was her past like as Celestia's student before she decided she wanted power, maybe her interactions with the school body. How did someone who doesn't understand friendship get to be so popular she won the crown the previous years? Why did she want to win the crown the previous years, when there were no real stakes behind it? Those are the questions a story like this could answer.

I also think that if you want to keep it as, basically, a retelling of Sunset's life, you could punch it up with a framing sequence. Sunset is sick or injured and reflecting on her life. Sunset is writing her memoirs. Sunset is reminded of her past by an encounter with a filly who reminds her of herself. That kind of thing. If you do it that way, it's important to maintain a thematic linkage -- so Sunset's memories of the past should end up influencing her present in some way.