Why Sunset Simmer's Plan from the First Equestria Girls movie would fall? 

I think that was kind of the point. Sunset was never a threat to Equestria, she was only a threat to herself and the humans. Her loneliness and superiority complex drove her a bit insane. Then meeting Twilight made her understand why she didn't get what she thought she deserved. It's interesting that Sunset didn't listen when Celestia gave her advice, but she listened to Twilight who led by example. We see almost the same thing play out with Luster Dawn in the series finale.

Sunset: *Enters Equestria with a bunch of unarmed teenagers* The three princesses, Royal Guard, and Mane 5 waiting on the other side:

[About the ages]: Both "sets" of the Mane Six (ponies & humans) have the same age. Time does not flow different on each world (the length of each day/night is different in seconds/heartbeats; because in Equestria is controled by Celestia & Luna using arbitrary units). | . Ponies spend less ammount of time on each of the in-between stages of their lifecycle because their magic "speeds up" their growth/development. | -> The "teenager" form of pony!Fluttershy seen the day of the Sonic Rainboom (Spike's Hatchday) only lasts for a few months. - - - The reason why Sci!Twi is still a unicorn is because she was NOT disintegrated (un-alived) & reincarnated (like Magi!Twilight, the Princess); but only "transformed". She always reverts back to her "True Form" of a human, or the equivalent in Equestria (a unicorn), that was also the case in the past for the pony Twilight. | In the case of Celestia, Luna & Amore (currently reincarnated as Cadance); their human counterparts live normal recurrent lives with "cycles" were they they suddendly "stop living" in their bodies at a certain age [when they would no longer reflect the "youth" of theur alicorn pony counterparts] & then are conceived in a another place of the human world (from a woman that shares the same distant ancestor than all of their "othet mothers" throughout history). They always look the same, no matter who was their father (or how different they may look from their "current iteration" mother). -> If the mother of the newest human Celestia dies, Luna will be born as her cousin, not her sister. They WILL "find each others" eventually (guided by dreams & visions). | . They are always sterile, just like their pony counterparts (Flurry Heart was an anomaly created thanks to the lack of magic of Cadance during the night before Tirek's attack; she was supposed to be just a normal random unicorn born from any other mare).

She really thought that a bunch of teenagers would be able to take on the equivalent of her world’s military.😂

Here's a random question: Why is it what Sci-Twi, being a unicorn in the pony world, gets the full alicorn treatment in the human world? Seriously- Why does she have wings??? This makes no sense!!!

[About satan!Sunset's Master Plan]: . She always intended to "gain power" & overthrone Celestia by force (eventually), IF her grandiosity was not recognized by her mentor. -> She had NO IDEA what the Element of Magic was actually cappable of doing (she just knew it was more powerful than Celestia), because Sunset can literally FEEL magic (even as a human), she explicitly says so in Legend of Everfree, inside the crystal cave of tge quarry. | . In EQG1, on the few hours between the arrival by train of the Mane Six to the Crystal Empire & the moment Sunset goes back to CHS to bring the "fake crown"; she was collecting information from random ponies present on the Crystal Castle (using a unicorn spell similar to what she would do later as a human with a geod; the kind of spell that makes the "hanging memories" over the cutiemap, or the book of Starlight in the special "Friendship is Forever"). | . Sunset likely believed that the same "demon empowerment" she gave to herself, Snips& Snails (fake alicorns, just like Cozy Glow did later), could be replicated to every single "teenager zombie" on the other side (if necesary). But doing so may risk "depowering" the Element of Magic (and/or losing control over each "super-zombie". | She prefers instead a "blitz" of locus-like lower minded ponies overwhelming the few defenses of the the Crystal Empire in a chaotic manner, herself cowardly coming last to "check" if Celestia, Luna & Cadance are STILL guarding the mirror (rather than splitting up, trying to save crystal ponies from injuries). | -> Picking them one-by-one (with the help of Snips & Snails) would be the best strategy.

Yeah I’ve noticed this on a rewatch of nostalgia because let’s be Fr and honest about this sunset’s army would be easily down out like straight up just down like She-Demon sunset in both lust and hunger for power didn’t really thought of near think this through hasn’t she and let’s say… 3 princess along with the mane 5 and the entire crystal empire and canterlot’s military! against teenagers boom defeated and she-demon against Luna or Celestia’s wrath! *F A I L E D*

Its werid tho what is the human world counterpart of the Equestria ponies also turn into ponies as soon as they get into the portal also wouldn't there be doubles of everybody like she don't hear her self

Yeah, but me have a brain fart right now. At least you fix that up for me.

I think the reason sunset destroyed the rainbooms friendship was because it was the only thing that could bring all the students together to fight against because each are from completely different backgrounds rarity is a pretty popular fashion Easter who likes makeup clothes and fancy high class stuff flutter shy is a shy insecure animal loving girl rainbow dash is a prideful athletic jock and sports girl and Tom boy applejack is a hardworking country farm girl pinky pie is a goofy party loving happy go lucky party girl but despite that they became friends.

This Is Just A Theory But I Think Sunsets Plan Was Meant To Fail Because In The Comics Of The Fall Of Sunset Shimmer Sunset Was Practicing/Training Under The Guidance/Teacher/Mentor/Master Of Princess Celestia/Jedi Master Celestia She Studied Magic Most If Not All Of Her Life She Was Impatient Her Teacher/Master Told Her That Go Out & Make Friends But She Didn’t Want To & She Thought It Was More Important To Study Magic Than Going Out & Making Friends Because Princess Celestia Showed Sunset A Mirror That Showed Sunset’s Future What Sunset Saw Was Her Becoming More Powerful Then Her Teacher/Master Until One Night She Broke Into The Library To Find Any & All About The Mirror Until Her Teacher/Master Found Her In The Place That She Wasn’t Supposed To Be In Keeping Secrets From Her Student That’s When She Thought That Her Teacher Was Keeping All Secrets From Her Student That’s When Sunset Had Enough Of Her Teachers Guidance & Cutting Her Self Off From Magic & Never Reaching Her Full Potential