Since language majors due tend to incorporate literature and history of from the culture that language stems from, I think you'd be better off minoring in Russian. Since you are a native speaker, I'm sure you could skip all the language classes and jump into the literature and history courses, which are taught and spoken in that given language. That way its more like English speakers who major in English. Its about the literature and cultural aspects of the language, not learning the language itself. Speak to the department and see if there's a competency exam or if they will let you skip the intermediate and advanced language classes since you're a native speaker, and then fulfill your minor credit requirements by taking the literature courses.
Just taking the major because you already speak it would be incredibly lazy. Equally, don't be that "native speaker" who then fails. A kid speaking Spanish "since birth" failed miserably in the Intermediate Spanish class I took. Quite pathetic.