As per your concern I will let you know IAS exam age limit and here I will get details of exam.

Eligibility

Age Limit
A candidate must have attained the age of minimum 21 years and must not have attained the age of maximum 32 years

Education
The candidate must hold a PASS BACHELOR'S degree from any of the Universities

Candidates who have appeared or intend to appear for the final examination and are awaiting results are also eligible to apply for the Preliminary Examination.

All such candidates who qualify the Prelims examination must produce a proof of Pass Bachelor Degree to appear for the Civil Services Main Examination. This Degree has to be attached with their application for the Main Examinations

Candidates with professional and technical bachelor's degrees that are recognised by the Government are also eligible to apply example MBBS, BE etc

Nationality:
The candidate must be a citizen of India to be eligible for the Indian Administrative Service (IAS) and the Indian Police Service (IPS), for other services, a candidate must be either:

a citizen of India,

or a subject of Nepal,

or a subject of Bhutan,

or a Tibetan refugee

Selection process
Prelims Written Exam (Objective Type)

Mains Written Exam (Subjective Type)

Interview

Exam pattern
Preliminary examination – it consist of two exam papers both are objective and each paper carry 200 marks.

General studies paper 1 includes history, geography, polity, economics, IR & IS, ethics, integrity and aptitude science and technology and social issues and General studies paper 2 includes quantitative aptitude, verbal ability, data interpretation and decision making.

There is a negative marking for wrong answers & 1/3 marks deduction will be made from correct answer, there will be no negative marking for the unanswered questions.

Mains Examination – only those candidates who qualified civil services prelims exam are eligible for civil services mains examinations.

Main exam consist of 9 papers out of which two papers are only qualifying in nature & merit will be made on seven papers & out of 7 papers, 5 papers will be common & 2 papers will be chosen by the candidate.