confidence vs overconfidence

I am a CBSE Student with top 5 rankers till my +2.
due to my negligence I have written 12 attempts of my IPCC. I have done 1st group and articles too completed.

Now I have intense desire to get a rank at 24 years.

My attempts will be as follows:-

November 2017- IPCC gr-2
May 2018- final under new syllabus

is it my exaggeration to get a rank in 6 months final preparation that too under new syllabus?
or I can achieve it possibly?
please suggest me under the above case...