Hello Nk D,
Yes definitely,If you want to get admission in any college if you to firstly clewr your 12th in every subject.Only then your are eligible to get admission in any college to persue your graduation. Whether it is IIT,NIT or any other college,to get admission you have to firstly clear your higher secondary education only then you can get admission there. Also your percentage should be under the required percentage for that college in which you want to get admission.