Is the little bit of nervousness is a worse point of the interview?

Definitely not. It never ruins an interviewee's chance to land a job. Interviewers -and employers- are aware of this fact. On the contrary, showing signs of nervousness is expected, especially by those who need the job most. 

Dear Bharat, Nervousness is what the state of our mind at the time of interview. For example..for an fresher who gonna take up his first interview..even if he full techocrat..well versed with all requirements required for the job..there would be some minute nervous feeling in him that whether he can crack and be successful.We must be strong and confident so..the idea of being nervous vanishes away in us...

Wish you a good day