Am I eligible to join 5 Year BA LLB course after completion of 12 Standard??

B.A. L.L.B. or Bachelor of Arts and Bachelor of Legislative Law is an undergraduate Administrative Law professional degree course.

Duration:
The duration of the course is five years on integrated basis.

Yes, you are definitely eligible to join 5 Year BA LLB course after completion of 12 Standard

B.A. L.L.B. Eligibility
Must have passed 10+2 or equivalent examination with minimum 50% marks in the aggregate

Some of the Entrance Exam after 12th for LLB Course Admission

Common Law Admission Test (CLAT)
Kerala Law Entrance Examination
Law School Admission Test—India (LSAT)
NALSAR Entrance Test
NLU Delhi Exam Notification
National Law School of India University (NLSIU) Entrance Test
Rajasthan University LLB Entrance Test or RULET exam
NUALS BA LLB entrance Exam
GGSIPU-CET BA LLB Entrance Exam

Reference books for 12th students for LLB Preparation
Bakshi & D.K. Kapoor
LLB Entrance Exam Guide by Ravi Chopra
Truemans L.L.B. Entrance Examinations by Sajit Kumar
CLAT by Mazumdar Rituparna
Study Package For CLAT And LLB Entrance Examination By Bharadwaj (Tata Mcgraw Hill)Arihant LLB Entrance Examination (Self Study Guide) by Dharmendra Mittal,S.P.
PRIME Tutor
Paradygm A & R
Career Launcher
LST
M.S. Coaching Center
LLB entrance exam guide (Asian books private ltd)
Coaching centers for the LLB Entrance Exam after 12th
Abhyaas
Sriram Law Academy
Career Shapers Education Forum
The Nalanda education and coaching centre
IMS
T.I.M.E