Yes you can appear for CLAT even after completing your Graduation in BA. After completing BA programme you can apply for CLAT Entrance exam. CLAT is the national level exam for the admission to Five year integrated programme & Post Graduate law ( LLM) programme and if you have already completed your Graduation programme then you can also go for 3 Years law programme.

If you want to go for five years Integrated law programme then to apply for CLAT you should have minimum 45% in your 10+2