Yes. @NJRoadie is completely right.
Regardless of your major during your undergraduate education, GMS will fund it for up to 5 years.
However, GMS will ONLY fund your GRADUATE education (for up to 5 years) if it falls under one of those categories of: computer science, education, engineering, library science, mathematics, public health, and the sciences. There are specific restrictions on these and will be specified to awarded scholars.
People change their majors often too, changing it from one of those specified fields to another will not affect your scholarship whatsoever. In short, you are not at a disadvantage.