You might get all three starters (but probably won’t get to keep them)

Like previous versions, Pokémon Scarlet and Violet feature three starters: the fire-type lizard Fuecoco; the grass-type kitten Sprigatito (dibs); and the water-type Quaxley, a duck Pokémon who was memed into oblivion upon its reveal earlier this year.
One NPC trainer, Nemona, says, “Are you these three’s trainer?” A few seconds later, you’re battling her in “your first Pokémon battle.” That battle then cycles through footage of all three of the new starters—which, to be fair, is possibly just for marketing purposes. Also, language on the official Pokémon site says you’ll “choose your first partner” from the three starters. So this is something that’ll likely remain up in the air until closer to the game’s November 18 release on Nintendo Switch. But, man, that’d be so nice to use all two of the starters (sorry not sorry, Quaxly fans).