Why doesn't my Keldeo's ordinary form appear in your Y pokedex?

Keldeo's Ordinary Form may not appear in your Pokémon Y Pokédex because it is not available in that game. Keldeo is a mythical Pokémon that was primarily distributed through events, and its Ordinary Form can only be seen in certain games or through specific methods, like transformations from its Resolute Form. If you haven't obtained Keldeo or haven't triggered its form changes, it won't show up in your Pokédex.