I have schored 55.2 percentage in class 12 with state board, will it affect be bad if I want to purchase my career in law at placement time?
After class 12th specially in law your knowledge skills and understanding will main factors for good opportunities and even your communication skills will depend for your success not your 12th percentage.
All the best

Not bad
It depends on how you do in your college
But definitely it will sometimes effect.