The official Pokémon Scarlet and Violet website has announced the Age Divisions for 2023 official competitions.

Age Divisions for 2023 Official Competition

All 2023 Official Competitions will be held using the following age divisions.

Age Divisions

Junior Division: Born in or after 2011
Senior Division: Born between 2007 and 2010
Masters Division: Born in or before 2006

Some Official Competitions may be restricted to certain locations or age divisions. Your eligibility for the Official Competitions provided by the Online Competitions feature will be based on the competition location and the age division you’ve selected.

How to Set Your Competition Location and Age Division

After opening the Poké Portal, select Battle Stadium and then Online Competitions. There, you’ll be able to set your competition location and age division. Please select the correct competition location and age division. To change competition location or age division settings, open the Poké Portal, select Battle Stadium, and then select Online Competitions. Then, select Change location or age division.

Caution

Once you’ve signed up for a competition, you will not be able to change the competition location or age division settings until the event is completed.

What Are Official Competitions?

Official Competitions are special competitions that use specified rules and are held officially, either live or online. Detailed competition schedules and regulations will be announced in the Poké Portal News.

To check the latest Poké Portal News, open the Poké Portal, press the L Button to connect to the internet, and then press the + Button if the Poké Portal News does not open automatically.

Note: In addition to Official Competitions, the Online Competitions feature allows anyone to hold Friendly Competitions.

Source: https://sv-news.pokemon.co.jp/en/page/38.html