I know this is fake, so don't say stuff like "This is not true at all", I know it is, but this is just a small theory.

Here goes:

Prim Hemlime has a more angular muzzle than most mares, and is has a muzzle more like Princess Celestia's, Princess Luna, Princess Cadance and Fleur dis lee, right ? And her legs are more longer and thinner, like their's, so maybe Prim could be related to any of these four ponies (Celestia would be exciting, but Fleur is more like it).

I know this is fake, but what do you think ?