How to create a dynamic marks filling table

Question

I have to create SQL server database table for student performance system. IN this admin have the authority to create a feature list and marks on which student will be judge. this feature list can have many layers(at the starting it have 3 layer) Like main category

1. Attendance
2. Character
3. Work Performance
4. Class performance

Now these categories have their subcategories

1. attendance
    1.1    a 
    1.2    b
2. Character
    2.1 c
    2.2 d

and so on...

now these sub categories also have their child categories

1.1   a
      1.1.1 a1
      1.1.2 a2
      1.1.3 a3

and so on...

Now Problem is that how to create marks filling table. if the main table is like this

Main category

MaincatID   Name         Marks
1           attandance   100
2           Character    100
3           Performance  100

subcategory1

sub1  MaincatID      Name      Marks
1      1             a         50
2      1             b         25
3      1             c         25

subcategory2

sub2  sub1      Name      Marks
1      1             a         17
2      1             b         16.50
3      1             c         16.50

so if bow create its marks filling table than it would be.....

marks_sub student ID    sub2        Marks
1              1         1          10
2              1         2          10
3              1         3          15 

if we fill marks in this manner than every student take at least 5-6 row . if there are 5000 student than it will become very large data set table

is there any other manner , in which we can store the marks of student. Please Help