Your 80 percentile isn't bad. U stand a decent chance for IIT.

U revise what u v done so far thoroughly.  Anyway, u v completed  most of the syllabus which is a god sign.

Plus, the fact that u r finding JEE 2007 none too difficult  is another positive indicator.

 

I v this gut feel that u wd make it to IIT.Best of luck on the D day !