Whether Correspondance(external) Student Can Persue Llb?

First of all, if you are not a graduate, no question of Admission into LL. B 3 years course arises,

no it's not possible. you have to complete your graduation first then join 3 years regular L.L.B. otherwise join 5 years regular L.L.B.

Please try for another University who can allow you because as far as LL.B is concerned it should be studied full time. Your previous degree which is partially done in external mode can be allowed subject to the university relaxation. Also clearing CET for law course also determines that you have the acumen for pursuing law. Try your best. You shall succeed.

after completing b.com (degree) join 3yr llb or join B.com.L.L.B., 5yr

no