Hello,
It is better to join at a coaching institute. That way you will be exposed to many things that you cant get exposed during self study. You will learn to develop your thinking skills, you can work sharp. I am not saying self study is bad. I am saying coaching institutes are slightly better. Or you can do one thing, you can take as many mock tests as possible to know your progress. So, you can assess and work on your weaknesses.
Good Luck!