NIOS is the largest open school in the world and is very popular in the commonwealth countries.NIOS is only authorised to provide education at Secondary and senior secondary level but not for graduation and post graduation level.NIOS does not provide any education at graduation level through its certificate for secondary and senior secondary level are approved to get admission in any University or institute all over India.In case of requirement of 10+2+3 pattern,you will have to take up the senior secondary course through the NIOS.There is no age bar for this institute.Nios accepts students from every government recognized body.You can opt for ODES,on demand examination,this mode allows you to appear for senior secondary examination for these two subjects.After passing exam you will get only one marksheet from Open School Board.