Union Government
A person shall not be qualified to be chosen to fill a seat in Parliament unless he - (a) is a citizen of India, and makes and subscribes the prescribed oath or affirmation; (b) is not less than thirty years of age for the Council of States and not less than twenty-five years of age for the House of the People; and (c) possesses such other qualifications as Parliament may prescribe by law.
To become a Member of Parliament, a person must be an Indian citizen who takes the prescribed oath, and must meet a minimum age - 30 for the Rajya Sabha, 25 for the Lok Sabha - along with any additional qualifications Parliament sets by law.
This is why a 23-year-old, however popular, cannot yet contest for a Lok Sabha seat - they would need to wait until they turn 25 to meet the minimum age qualification under Article 84(b).