I am an FY B.Com student. Can I appear for TY B.Com exam directly after completing FY B.Com?

No, you need to go through the process i.e. you need to clear the second year only then you could go for the third year.

Dear, You can't give third-year exam immediately after the first year. Firstly, you need to clear the second year then only you can appear for the third year. You have to follow the pattern as set by UGC. All the best