@Background Pony #C343
Fluttershy is only older than Pinkie. But there are also other things that can help your theory, she’s have longest legs and hair among the mane 6. Celestia has the longest legs and hair of all of MLP. Fluttershy’s Rainbow Power resembles Celestia’s color patterns, pink, blue green, and purple. Fluttershy has somewhat of earth pony magic.
Celestia - uber ancient thousands of years old demigod princess pony
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Discord - ancient spirit of chaos
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Pinkie Pie - 4th wall breaking trickster pony from before Equestria was made
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Fluttershy - 1 year older thank Pinkie Pie
Hm. She did have a wagon in “Feeling Pinkie Keen” and some of those cars had trailer hitches to tow stuff with, And they could transport 8 or 9 passengers and have stuff on the roof-rack.
In my headcanon, Fluttershy is the long lost daughter of Celestia…cute, pink hair when young, misteriously older than the rest of the mane 6, dresses quite fine as Shylestia, with no parents around, some crazy super powers and animal understanding, was chosen by Celestia as defacto Discord reformer, and gets along with the beast.
Of course she would want a batallion of brothers and sisters.