Dear aspirant

The Union Public Service Commission prescribes the age limit in the official UPSC IAS notification 2023. As per the IAS age limit eligibility criteria, those between 21 to 32 years as on August 1, 2023, can fill the UPSC IAS application form.

You will be 21 year's old on 5th September 2024 only but you should be 21 year's old before August 1,2024.

So you will not be eligible for 2024 session,you may be only eligible for 2025.

You can check details about eligibility criteria from link below

https://www.google.com/amp/s/competition.careers360.com/articles/upsc-ias-eligibility-criteria/amp

Hope this information helps you

All the best