April 24, 2020
This is a question for your guidance counselor and not for "The Dean" because different schools handle high school classes taken during middle school in different ways. And I have actually never encountered 8th graders taking high school art courses, although I have advised gazillions of 8th graders who took high school math and foreign languages.
Most commonly, when an 8th grader enrolls in a high school class, the credit is listed on the high school transcript so that the college folks know that the class has been taken. Often—but not always—the grade received in the class is listed, too—but very rarely is that grade included in the student's cumulative GPA.
So you need to ask officials at your school how they will report your class. Chances are good that it won't be reported at all. But, if it is, you may have some leeway to request that it be omitted if you don't want it there.
In any case, this isn't something you need to worry about. Even if you finish the class with a C, there is not much chance that this grade will be included in your high school GPA. And even if college admission officials were to spot that C on your transcript, it will not in any way affect their evaluation of you. The fact that we're talking about an art class (which they will view as a non-academic subject) and the fact that you took it in 8th grade will make it a non-issue. Even if you were to eventually decide to attend an art college or apply to any college as an art major, your 8th grade performance will not impact your future acceptances.
I must say, however, that I'm intrigued by the fact that you're getting a C in art, where grades are often based on effort and attitude as much as on talent. Are you just an average artist or are you messing around in class or missing assignments? It does sound like you might be able to pull up your grade with added attention. If you haven't done so already, ask your teacher what you might do to improve.