Yes sir, i understand your query regarding to this so i would like to answer you as follows:

Yes Definately You are Eligible to appear In the IIT JEE Entrance Examinations. So, if you have Completed Your 12th Then You are Eligible to appear In IIT JEE Examinations.

Because it is Clearly Mention that If the Student can Pass In Senior Secondary School Examination conducted by the National Open School with a minimum of five subjects Are eligible to appear In the IIT JEE Entrance exams.

So, dont worry About that Just Concentrate In Your Study And Focus To the Clear of IIT JEE Exams with Good Marks.

Imif you still have any query related to this ask me in comments