You are saying that you got “Bs” because you got “80 out of 100” and now you are doing bad because you are getting “60 out of 100.”
What I am trying to explain is that different systems have different cutoffs for their grading.
For example, in IB HL Math, if you get above a 74 - you get the HIGHEST possible grade (a 7). But a 74% in the US system is only a C. So basically - a 74 in one system is NOT the same as a 74 in another system.
So you are “doing bad” because you are gettting a 60. But colleges will compare you to other CBSE students (they get lots of applications and your application will be reviewed by someone familiar with the CBSE system most likely). If a 60 is “good” in the CBSE system…they will read it as a good 60 and not a bad 60. CBSE is notoriously difficult and my guess is that the grade boundaries are much lower than they are in the US.
Does that make sense?
In effect you are comparing apples and oranges instead of apples to apples.