hi,

see to apply for national merit cum means scholarship you dont need to wait upto 10th exam, you may apply for nmms scholarship once you pass your 8th standard exam, the eligibility criteria is,

The candidate  must pass class 8th with a minimum of 55% marks (50% for SC/ST) in order to become eligible for the nmms scholarship 2020-21.

Students need  to appear and qualify for the NMMS exam.

the family income of the candidate must not exceed Rs.1,50,000.

however Students of Kendriya Vidyalaya and Jawahar Vavodaya Vidyalaya, Sainik Schools, students who are studying in the residential/boarding schools run by the State Government Institutions are not eligible for the NMMS Scholarship.

follow the below link to know in details,

https://school.careers360.com/articles/nmms-scholarship