It is always better to go for both groups, but considering your case, if you havent prepared group 1, then try to put some more efforts on your practice. The only way to get success is to practice alot. Try to get maximum marks in your scoring subject. Dont leave any chapter as choice,try to gain minimum understanding on each and every topic. Write a couple of mock tests under exam conditions. Try to attempt 100 marks in the examination.
Dont worry about past, take it as experience, be positive, you will surely pass this time....all the best..cheers