I receive a letter of war, magic and a second puberty

Hero Perspective
Earth
Rainbow Dash's POV

I made my way to the man's house in a crash from my change in physical features. On the plus side, I also created an awesome double rainboom! Achieved only by added speed from my unexpected free fall.
Twilight mentioned this transformation when she told me how to get here. Something about alternate realty hoo-ha she learned about during her quest to get her crown back from this world. But I tuned her out during most of her speech and missed the part on how to use my body in this world. I payed the price harshly, almost every inch of me was either bleeding or sore. I remembered vaguely how twilight told me to stand like Spike on two legs for it was easier to do than all fours.
As I stumbled to whatever my elongated hooves were, which I think she said were called "Foots", he began to stare and gape at me.

StarBlitz's POV

I just stared in complete disbelief what I was seeing. Right in front of me was the real Rainbow Dash. I am a brony, but only my friends know. We use to love the show back in the sixth grade and we had our own OCs.
But right now, I couldn't process any of what I was looking at. Next to that were the questions that I had; how did she get here?; Why is she here?; Why does she exist?; Why is she human!? My brain raced and the silence was broken when she asked me a question.
"Are you StarBlitz?",
How did she know my name?
"Y-yes, why?"
"Because I'm here to deliver a letter". She reaches into her pocket and pulls out a envelope.
A letter!? Who in Equestria would send me a letter!?
"A-are you sure it's n-not for somebody else?"
"Yes, I'm pretty sure. Anyways, it's for you and two others- do you know a Skywriter and Badger?" She looks over my shoulder and all around
How did she know all of this?!
"Yes I d-do"
"Well go take this to em' and it will tell you all that you need to know. Oh, and fix that stutter of yours. Gotta Dash! Hehe...always wanted to say that" and with that, she awkwardly flew off, made a quick, but decent sonic rainboom and was gone.
I ran all the way to their houses, I guess I'm lucky that they still live in the area. I arrived at Skywriters house first and she came out in her favorite turquoise blouse, I'm surprised it still fits her after all these years, along with her moon and quill charm dangling from her neck. Her eyes a cold and icey blue and her streak shined brighter than ever.
Our streaks were another part of our many anomalies. Each of our streaks was a patch, lock or clump of a few strands of hair that looked unnatural and dyed, but were quite the opposite. Her streak was a long line in her hair made of two thin stripes of minty blue and aquamarine, mine was a big patch of tangerine hair with brilliant red strokes at the end and Badger's was a murder on my eyes, zigzag of black and white that pushed outward from the top of his head.
Whenever a streak was cut or shaved off, it grew back the next day as long as it was before it was cut, but with the same color of our regular hair, and then changed back to its streak color the day after that.
Skywriter was surprised to see me since I haven't visited before. I tried to explain to her what had happened but after a long silence, she replied with something along the lines of, "Okay, you've read way too much fanfiction".
She didn't believe me one bit. I even showed her the letter's address but that didn't work either.
"Just come with me to find Badger and I'll show you the orphanage"
"Uuuugh... Fine"
After an long hour of being called delusional and mental, we arrived at Badger's place and found out that he was home.
"Hey guys! How's it go-"
"I'm not even gonna try to tell you, so come with us to the orphanage".
"What? Its like, 8am man! Why are you even here anyways?"
"We are here to begin your mandatory physical for test subjects under: 50, days of-"
"Ha ha, very funny. Now seriously, why are you here?"
"I'll explain later. Now come on, we gotta get going"
With a sigh, he got dressed into a cyan T-shirt and some sweat pants and locked the door behind him. I felt a chilled breeze on my shoulder and noticed a hole that was singed through my jacket.
"Oh come on! that was my favorite jacket!" I took off the scarlet windbreaker and tied it around my waist while muttering, "Dumb fabric...". We drove to the orphanage in his car and I explained everything about what happened, and of course, he didn't believe me and I suffered the same torment Sky gave me, but he learned quickly when he saw the giant hole on the front lawn with rainbow fire dancing along it's broad rim.
"Isn't that where the old shed used to be, Blitz?", he asked weakly.
After we got out of the car, we headed over to the new dugout and sat down at the edge. Badger looked at the fire and went to touch it, "Wow! It isn't even hot!"
"Why would you even- never mind."
I pulled out the letter and began to read aloud.

"Dear Star Blitz, Skywriter and Badger,

I have to inform you that a world other than your's exists and it is where you are originally from. It is known as Equestria and you need to come quickly. A terrible crisis has occurred and your help is needed desperately.
Magical objects known as, 'The Elements of Harmony' are this world's strongest protection, but somehow, Equestria's most powerful villains have found a weapon with power far beyond that of the Elements and they are using it to rage war and to gain power. The only way to stop them is with a weapon with power similar to their's and it has been entrusted with you three.
With this method I prepared, you can return to Equestria to learn more of the war and to use the device in battle, but you must first perform the steps listed below to complete a transformation that will allow you to come to Equestria.
The one of little
who you can trust,
Princess Celestia"