Hello dear, 

Thanks for contacting us. 

Yes, you are eligible for cpt exam after completing your 12th. The eligibility for cpt is given below: 

• Candidate must have passed 12th from any national or state recognised board of secondary education in india.
• Candidates mush have registered/switched over to common proficiency course with board of studies of ICAI on or before june 30,2017
• Candidates CPT registeration must not have expired
•  Candidates applying for CA CPT 2018 June examination must have a valid registeration Id as at the time of filling application form.

I hope this will help you. 

All the best!