How can I overcome my fear of moving to the USA?

Are you moving to Southern California, or was that just were you visited? Many places, especially the large cities, rely mostly on walking and taking the train. In Chicago, most people walk or take public transportation. Also, it sounds like you have a wonderful sense of fashion. Don't change who you are and how you dress just because your geography changes. Americans are proud of their diversity, and your unique style is something that will be appreciated. Don't worry. I believe you will make the transition fine. Just be proud of who you are, and be patient.