The language advice is very good. I am starting a masters programs in the Fall and am fairly certain that I will be focused on early 20th century Latin American art, but who knows? I've changed my mind a thousand times. I double majored in art history and archaeology, loving Modern and Contemporary art the whole time. I started out as an Ancient Roman enthusiast who went to college on a Latin scholarship. I am constantly torn between loving ancient art and archaeology, and being fascinated by the complexities of Modern art. The only modest advice I can offer is to also consider your future job prospects, lifestyle etc. That has helped me. I love Latin and Ancient Roman archaeology, but it's not really the world in which I'd like to work. I like Contemporary art, but I'm really uninterested in the art market. I want a job that will hopefully allow for some travel, and besides being fascinated by Latin American arts, cultures, and traditions, I love traveling there.
I am just starting out, so I don't pretend to know much, but I think many people don't take into account that how you envision your career, the people you work with, where you live, and your lifestyle can help to give perspective on choices such as these. That being said, I think you've got plenty of chances to change your mind and figure out what you want. The worst decision would be limiting yourself because you've 'made your bed and now you have to sleep in it.'