There's a good chance you can pursue M.Sc. in Clinical Psychology with a BCA background, but there might be some additional steps involved. Here's a breakdown of the eligibility criteria:

General Eligibility:

• Most universities require a Bachelor's degree in Psychology for M.Sc. in Clinical Psychology.
• However, some universities allow students with degrees in related fields like Social Work, Sociology, or even non-science backgrounds to apply, provided they have some psychology courses in their undergraduate studies.

Your Situation:

• With a BCA degree, you wouldn't have the standard psychology background.

What You Can Do:

Check University Requirements: Research universities offering M.Sc. in Clinical Psychology and see their specific eligibility criteria. Some might allow applications from non-psychology backgrounds, especially if you've taken some psychology courses during your BCA or PUC.

Consider a bridging course: Some universities might offer bridging courses in psychology for students from non-psychology backgrounds. Completing such a course could strengthen your application.

Focus on relevant skills: Highlight relevant skills from your BCA education, such as research skills, data analysis, and communication, which can be valuable in psychology research.

Entrance Exams: Many universities require entrance exams for M.Sc. Clinical Psychology. Perform well in these exams to showcase your aptitude for the field.

Can you do it now?

Since you're still in your 3rd year of BCA, you have time to research and prepare.

• Look into universities and their eligibility criteria.
• See if there are bridging courses you can take.
• Start preparing for entrance exams (if applicable).

Additional Tips:

• Consider contacting the admissions department of universities you're interested in and inquire about their specific requirements for non-psychology backgrounds.
• You could also connect with current students or alumni of M.Sc. Clinical Psychology programs to understand their experiences.
  
  I hope it helps you.