If I have a 65 average but the cohort average is 75

[IM_NOT_SMARY]

If I have a lower average than my cohort for English, does it mean it’s impossible to get a 30 ss, let’s say I have 65 average for English but the average for English is 75 what does his mean what will my study score be

[The Cat In The Hat]

Depending on your performance in the exam, you can get a 30+. It's not a bell curve of your class, nor is your ranking pre-exam necessarily what you will get as a study score. So for example, if you're ranked last in a class of 300, as an arbitrary example, and yet fullmark the exam, you can still get a 30+ (I think).
So don't worry about it, just do your best

[Sine]

If I have a lower average than my cohort for English, does it mean it’s impossible to get a 30 ss, let’s say I have 65 average for English but the average for English is 75 what does his mean what will my study score be

You can still get a 30+ ss you just need to get that type of score on your exam.

Your cohort could also be strong so a less than average sac score may correlate to an average study score.