The answer(s) to your question depends on what is your objective behind doing LLB.

After 12th, one can pursue a 5 year integrated BA LLB. You can appear for CLAT or various other law entrance exams and get an admission in BA LLB once you qualify the test. There is no age limit to study law after the 3rd March order of the Supreme Court. But in this case you have to quit your job as it is a full time course.

However, if you do not want to quit your job, you can go for distance learning/Correspondence. There is a list of colleges that provide this option. http://www.delhilawacademy.com/study-llb-in-distance-learning-mode/ . However this degree is not acknowledged by the Bar Council of India and therefore, you will not be eligible to practice as a lawyer in a court of law. So if your objective to learn and understand the law rather than make it your profession, you can choose this option. You will still have many job opportunities after this degree. You can be an associate with a corporate law firm, a legal department in a company or apply to organizations which prefer applicants with legal background.

There is still another way. First, you complete your BA via distance learning and then enroll yourself in a 3 year LLB program. There are some colleges/universities which give the option to study in evening. With the permission of your department, you can pursue LLB while keeping your day job. And this degree is approved by BCI and therefore, once you finish the studies and enroll yourself with the Bar council of your state, you can practice law.

So think about all the options and choose the one that suits you best. If you have more question, feel free to ask. all the best