(Timeskip - 3 years later)

Mom had begun teaching us how to read and count (turns out math here is in base 10; that would make things easier) and... attempted to get us to speak, with mixed results. Most of the time we "spoke" with actions. Fire Fox and I started using what we later called "twin-speak"; we could understand each other perfectly, but no one else could.

We started to teach each other how to read at the same time; We would help each other out on the words that the other wouldn't quite get on the first try. It was when we were three years old that we spoke our first actual sentence together:

"Mom, can we have some ice cream, pleeease?"

Suddenly, a window appeared in front of us, slightly to the side.

Achievement Unlocked: Double Entendre

(1)

Fire Fox and I looked to each other and high-hoofed.

Mom, for her part, seemed delighted. "And since you asked so politely (and actually asked, period), I'll get you some." she said. I could tell that she wanted to do more, but ice cream would be enough.

Fire Fox, as it turned out, liked Prench Vanilla flavour above all others. My favourite was Caramel Chocolate Chunk. That was one of the few differences we displayed (aside from our outward appearances, of course).

At first.

(Timeskip again - 3 more years hence)

Being an Earth Pony, my sister started to show talent with hot-house plants. She could even make them grow in the depth of winter. Someday soon, the literal fruits of her labours would start to be distributed across the country.

Achievement Unlocked: Taking on the Heat

I, myself, came up with a sort of... invention I would come to call "vapour script". All it took was a moistened puff of air and some Pegasus magic (some intent added in), and I would get a scroll of sorts, made of air. From there, I just had to write down the correct spell formula, and add some energy to it. Thusly, the spell would be cast.

Achievement Unlocked: Vaping On the Clock

Hey!

Amended: Air Brushing

Better.

Anyway, soon enough something... Interesting happened...

At one point, I was practicing with my flying, close to the ground. I had just gone into an updraft, to gain some height, when an explosion happened! I was close enough to it that I was blown back into the ground, about 50 meters below me.

Fortunately, Pegasi are tough.

A circular rainbow spread from the source of the explosion, whatever it was, and seeing it made me want to spread the beauty of that chromatic corona across the country, if not the world. (2)

At that point, I felt a tingle on my legs and my wings. When I looked back, I found two things.

1: I had just gained my Cutie Mark! It was a hoop of red, blue, green and yellow...

2: Much like my wings! My primers had changed colour, alternating between red, blue, greeen and yellow.

Just about then, I saw a cactus shoot up through Fire Fox's greenhouse and, naturally being worried about her safety, took wing and dashed to her rescue.

When I got there, I found that Fire Fox's hot-house horticultural hoard had exploded in growth! Some of them, literally! And JEEZ! It had to be at least 150 degrees in there! What also surprised me was that there was a circle of sorts around the lot of them. None of the plants went outside of the circle.

Just outside of it, panting and wheezing, was my sister. When she looked over at me, she gave me a wan smile. Her mane -previously flowy and all- was lying flat, a dull yellow in colour. It seems that in (presumably) charging the spell she had just cast, she used up just about all of her energy. 'Just about' because she was still -albeit rather shakily- able to stand up.

However, it seems that she also got her Cutie Mark! It had a fox made of flame encircling the world.

She later told me that when that shockwave hit, she knew that if she didn't do something then pieces of her little hydroponic hut would explode and send shrapnel everywhere! She suddenly felt the need to protect the whole world from danger; to protect everypony with all of her energy. Then she instinctively knew what runes she had to use to stop that from happening. She suddenly found that time sort of... slowed for her, and she used the "extra time" to draw the spell as fast as possible.

I helped her outside, to get her some fresh air. Looking up, we could see a trail of colour blazing across the sky. The two of us just knew that we would have to go in that direction. We just had to go there, someday VERY soon. It felt like... fate was calling us.

Buuuuut for now...

We dashed toward home, excited to show off our new Cutie Marks to mom and dad.

While celebrating with her family, Pinkie Pie felt her knees wobble, and her hooves tingle. She had the feeling that somepony else neded a party too. She knew that she'd know who it was when she met them. But that it also meant that she'd have to leave her family's farm soon. But that would come later.

Some distance away, over in Manehattan, Applejack felt her soul being tugged in the direction of home, back to her family. Her Cutie Mark appeared just then, three apples, to represent the three Apples she cared for the most, and that she'd have to apologize to them for leaving them. To think that she'd thought the city life was for her. Ha! She resolved to leave the very next day.

Rainbow Dash, having landed safely, knew that she needed to head to somewhere she'd flown past. She decided that she would, someday soon, go there. With her parents' permission, of course. Her Cutie Mark had just appeared, so for the time being, she'd go home and show it off.

Over in Canterlot, Twilight Sparkle was leaping around her new mentor's hooves, exclaiming, "Yes! Yes! Yes! Yes! Yes!" She just knew that life was going to become more exciting for her. The starburst on her flanks shone brightly for a moment, as it appeared.

Over on the ground, surrounded by her new friends, Fluttershy decided right then and there that she'd make her home on the ground, where she could be with those who actually cared about her. Telling her new friends to wait for her, she flew back toward Cloudsdale at what some would call a leisurely clip, to tell her parents of her decision. The butterflies on her flanks glowed for a few seconds as she flew.

Over in the small town nearby, Rarity knew just what to do with the cache of gems she'd just found. Everypony would love the accents on the costumes she'd make with that! As a mark of three diamonds appeared on her flanks, her magic sparked again as -with much effort- she floated the gems one by one in the direction of home. There was so much that she needed to do...

Author's Note

1: More accurately, two single ones at the same time.
2: Yes, much like Pinkie Pie. And yes. I do plan on what you might be expecting.