After the first hour or two of Pokémon Scarlet and Violet, depending on how long you reach Mesagoza's Academy and leave on your treasure hunt, you'll be allowed to choose your own path. You'll be loosely directed down three paths: Herba Mystica, Victory Road, or Starfall Street. You can choose any option, but because the game has no level scaling, you can take a sort of "best path." Here is our recommendation.
Should I choose Victory Road, Herba Mystica or Team Starfall first in Pokémon Scarlet & Violet?
If you want to go by the lowest recommended level, head to Victory Road and Katy, the Bug-type Gym leader in Cortondo. However, the easiest challenges to take on in the Herba Mystica storyline and on Starfall Street are not very far off in level, so you could choose to start on any of these story paths if you choose.
It's important to remember that the three paths in Pokémon Scarlet and Violet are not designed to be completed on their own. You should expect to interweave tasks from all three paths on your treasure hunt around Paldea, as well as spend time simply wandering around. This can make your hunt for rare Pokémon to fill up your boxes and Pokédex easier.
Looking for more help in the start of Pokémon Scarlet and Violet? Check out Which Starter should you choose in Pokémon Scarlet & Violet? and How to use the Union Circle in Pokémon Scarlet & Violet here at Pro Game Guides.