Hello dear aspirant.
the eligibility criteria to get into Indian navy has a age bar of 21-24 years. So yes, if you’re 24 years old in 2021 you can apply this year and go through the entire recruitment procedure.
Completing graduation be it a regular degree or diploma with 60% aggregate or more in all semesters, As well as in physics and mathematics in 10+2,, makes you eligible to apply.
if you are eligible you can appear for INET, that is Indian Navy entrance test.

The tentative date to apply in the year 2021 will start from November 1st, 2021.

I hope this helps, please ask if you have any more queries.
Good luck