Nit picky note. Epona was never, at any point, a pony. She was a baby, called a foal (the broad general term for baby horses) or a Filly (female foals). Ponies are fully grown even if they are under 14 hands. A pony can never grow into a horse.
Would you consider Epona a palomino? Given her brown coat and white mane?
I think there's a bit of a typo here. Since when is Epona's tittle "princess of hyrule"?