Hello,

To be eligible for Indian Navy you must have Science in class 12, with Physics & Mathematics and English as mandatory subjects. So if you do commerce in your 10+2 level you will not be eligible for the Indian Navy. You will be eligible for The Indian Army but not the Navy or Air force. Entry into the Indian Navy is mostly through entrance exams like NDA/ NDA (Naval Academy) after class 12. So it's better if you do your 10+2 level with science rather than commerce. Please click the below link to know more.

https://www.careers360.com/careers/articles/how-to-join-indian-navy-after-12th-counar