I answered that already.
Graduating law school is easy, almost everyone who gets in finishes.
As for doing well:
As far as how well you will do in law school, you will probably be around the middle of the class. But there is a 25% chance you will be in the bottom quarter, and a 10% chance you will be in the bottom 10%. I am not aware of any method of accurately predicting this. LSAT score is the best predictor, but is not really excellent.