For UPSC CSE, the lower age limit is 21 years and it is required that the student must be 21 years of age before 1st August of the appearing year. Now, as you are turning 21 years before the 1st August,2023, you are eligible for the UPSC CSE examination 2023.

For more information regarding the eligibility criteria of UPSC IAS consider the link below:

https://competition.careers360.com/articles/upsc-ias-application-form#:~:text=UPSC%20IAS%20Eligibility%20Criteria%202022,-UPSC%20prescribes%20the&text=Candidates'%20UPSC%20IAS%20age%20limit,the%20UPSC%20IAS%202022%20exam.

I hope this helps. Wish you a great eve!