It is possible to get a Shiny starter in Pokémon Brilliant Diamond and Shining Pearl. At the start of every player's Pokémon journey, they are given the option to choose between three starter Pokémon.
In the case of Diamond and Pearl, players will be able to choose between Turtwig, Piplup, and Chimchar. While each Pokémon has its own strength and weaknesses, it will ultimately be the player's partner for the majority of the game.
Read more on screenrant.com