Yes,you will be able to do your degree in law after your 12th grade.You will have to  write the CLAT to get an admission into any Nationally recognized Law institutes.The exam will be pen-and-paper based and of two hours duration. CLAT is conducted for admission to 5-year integrated law and LLM courses.

Other common entrance exams for law are LSAT India (Law School Admission Test ),AIBE (All India Bar Exam),All India Law Entrance Test (AILET).To know more about these exams and to download their brochure,visit the below given website:

https://law.careers360.com/exams

All the best!!