Hi! How exciting. I think it depends on your goals and what programs you are considering -- most of the MA programs I looked at required at least 3 art history courses. I was not an art history major in undergrad, so I invested in a few courses at the local university and did everything I could to be a stellar student (within reason -- I was also working two jobs). Not only did I get a better foundation for my MA program, I gained a few more mentors who really helped me through the application process. I feel like it was worth it -- but everyone's situation is different. I wouldn't let your transcript keep you from applying -- just keep in mind you'll likely be competing against other folks with very strong backgrounds in the subject.