Creating a persona and expressing it in costume, manner, and other attributes is one way that some SCA members enjoy participating, but it's not required. Many members prefer a broader focus, or simply enjoy hanging out with friends at the SCA events while wearing the pre-17th century garb they find most comfortable. If you decide to go for the Award of Arms, you'll be required to choose a culture, century and historically plausible name for your chosen persona as well as a device (heraldic design), but there's no requirement to dress or act in the role of that persona. Many members have multiple personas of different regions of the world, centuries, genders, professions or classes.