Sunset Shimmer started out angry and ambitious, having fled to this world out of rebellion because (depending on the source) either felt she wasn’t progressing fast enough or wasn’t progressing at all under Celestia’s teaching, but still a good person. The kind of person who Celestia trusted and had an emotional bond with. The kind of person Flash would realistically start dating. She comes to this brand new world where everything’s new, the social rules are different and in her favour, and she isn’t Celestia’s prize pupil so the pressure’s off and she can do whatever she wants. In the first picture, she’s happy and grateful because she probably won that crown legitimately.
 
One year later, and she’s learned that her personality flaws aren’t hindrances in this world. She can just be an alpha bitch and there’s no Celestia or Royal Guards to stop her from getting what she wants; power over other people, and their respect.
 
The next year she is drunk off this power, has devolved into a vindictive, cruel person who rules the corridors and classrooms with fear.
 
The following year, the year Equestria Girls takes place, she’s reached the top. She unofficially rules the school with an iron hoof, and not only is her ambition not satisfied, but even the power she does have feels utterly empty and hollow. Flash has dumped her by this point (or she dumped him) and she’s utterly alone, but she’s still too proud to stop. She needs Equestrian magic. She’ll just keep digging this hole until she strikes gold.

@Yet One More Idiot  
Chamon! ;3

@The_Butcher  

 
Leems segit.
 
Also… uploaded by Background Pony
 
#BADD
 
The second D is for a Double Dose of BADDNESS. :P

@Darth Shy  
All grades can go to prom. Otherwise, seniors couldn’t bring the juniors they date.

@mercurypony  
I thought prom was only for the last year of high school?

Should have included the other prom photos lol.

@MeshGearFox  
In the prime universe maybe
 
but this is an alternate world so maybe this world’s Twilight is much longer

@The_Butcher  
…Sounds alright. X3

The Twist is that like her Toy description she is a Unicorn and was Celestia’s Student.  
But, unlike with Twilight, Celestia taught her more offensive Magic and she learned Mind Magic, like Memory Modification Spells.
 
Celestia has since learned that was a stupid thing to teach somepony.  
She escaped Celestia’s influence by going to earth.
 
She brainwashes rich couples to believe they are her parents (while they are more her slaves), is hundreds of years old and has attended High School for decades Because she can do anything there without anyone stopping her and she doesn’t have any responsibilities. Everybody just thinks it’s “High School Drama” when inconsistent stories about horrible magical experiments crop up and are soon forgotten. She can kidnap people and brainwash them afterwards and siphon their life Energy to make herself eternally young.
 
Human minds are so easily controlled…

@Klonoahedgehog  
Ah, I see. Apologies, then. :)

@thps48  
No offense?

@Klonoahedgehog  
Your mother. :\

@Klonoahedgehog
 
Eh…

@thps48  
Never make that joke again, Kingdom Hearts is too good for this.

I’ve got it! EG Equestria is the Door to Darkness… That or I shouldn’t play DDD on Listerine. XC

@Itsthinking  
Oh wow, I didn’t think I would hear that outside of my school.

Also let’s ship her with Dan.

If Sunset Shimmer is Celestia’s former student wouldn’t that make her at least 40?
 
That’s four times as many as ten, and that’s noooo good!

The “Human World” doesn’t exist.
 
It was all made my Summer Shimmer imagination and she rules over it.

She purposefully holds herself back because prom queen is the only thing she can achieve in life.  
Do not cry for her.

Freshmen, sophomore, this would be her third year in high school. So Junior, then senior.

First pic: Freshman  
Second pic: Sophomore
 
It’s that simple guys!

Hormones are a hell of a drug.

Oh wait. Twilight’s Element crown is somehow the prom crown, and to get it she’s got to beat this Undefeated Prom Queen Champion? By having the most friends? Yeah, I was starting to be interested, but now…ehhh.

@ROTHY  
It’s actually a term for failed to graduate.