You may pursue MCA after either of the two, B.Sc. or BCA. However, B.Sc. has more career options than BCA and who knows you may develop an Interest in some other domain. Hence, I would advise you to pursue a Full Time B.Sc. Degree and hence you may pursue MCA for a career in the IT/Software/Services Industry.

For more information about MCA do follow the link below

https://www.careers360.com/courses/mca-master-of-computer-applications/amp