The teacher marked the words "interests me" in the following sentence to be gramatically wrong, why? I think the sentence is gramatically correct.

> 
> "I never thought that I was going to be accepted straight into the
>  advanced level classes to learn the advanced material that interests
>  me and that will help me to get better grades in english exams."
> 
> 
> 

Someone had told me that it is because of the fact that the teacher might be a "prescriptivist" instead of a "descriptivist". Is that the only possible explanation for "interests me" beign marked as wrong there?

Or is there any grammar rule that says that it is gramatically wrong to write "interests me" there in that way?

Please note that in this case "interests me" refers to "the advanced material" so i think it's the same that in the sentence "I will do something that interests me" in this case "something" would be "the advanced english material". So since "I will do something that interests me" is gramatically OK ( i think because saying "something that interests me" is common ), then my sentence should be ok gramatically too then. What are your thoughts about this?

Your help is really apprecciated thanks.