If you be average student and want become big neurosurgeon, then no problem, you try try again and do smart study and keep focus always, you need pass 12th with PCB subjects good marks, then write NEET exam, get MBBS seat, after MBBS you go for MS or MCh in neurosurgery, all hard but not impossible, only you need time table study and good motivation.

1, study class 11 and 12 properly, especially biology chemistry physics

2, give NEET exam and try score more than 600 marks for good government college

3, complete MBBS degree 5.5 years, then prepare for PG

4, crack PG entrance like NEET PG or INI CET for neurosurgery

5, get seat in MCh neurosurgery which take 6 more years study

https://medicine.careers360.com/articles/how-to-become-neurosurgeon-in-india