Your eligible for CAT exam once You have completed your 2 years of graduation but CAT requires immense practice. scarcity of resources and lack of concentration might put a barrier to your selection in India's top B school.But the final answer of your question is yes! you can.
Yes B.com final year is eligible to give cat exam must have minimum 50% marks till final year. Cat exam is generally conducted in Nov/Dec month and its registration starts in month on august. Anyone who eligible can crack exam by hardwork.