I want to became CA. I am in std 12
CA CPT is the Entrance Exam you need to apply. You have to clear below levels in order to become a CA.
CPT (Common Proficiency Test)
IPCC/IPCE (Integrated Professional Competence Course)
Three years of Articleship under any C.A who is practicing the profession
CA Final Exam
You can check teh complete information about the exam with the given below link.
https://finance.careers360.com/articles/ca-cpt
Good Luck!