Twilight Sparkle, and her entire family, are nobles.

House Twilight is one of Canterlot's oldest noble houses, meaning that they carry a wealth and status very few in Equestria can lay claim to. Twilight Sparkle, throughout her life, hasn't really ever thought about this fact; she never even thought of herself as being in the same vein of the snobby Canterlotian Elite.

And then a terrible realization hit.