applying to university in America

Hi guys I'm applying to Cornell and duke university from the uk (plus other unis). My gcses 877666654 a level predicted grades A*A*A in maths physics and biology I got an A* in my epq i got a 1600 in my SAT. Some of my extracurriculars include fully funded summer school at imperial college for science, navy cadets, deputy house captain, president of eco committee, head of charity in my boarding house, maths scholar in school, engineering + hospital work experience, dofe bronze and silver, 1000+ hours of volunteering at care home hospital and children church, writer and part for the editorial team for school's science magazine . I'm apply for early decision for duke I'm worried that my gcses are extremely low so what are the odds that i'll get in? Also I went to state school all the way up to year 11 i go private school for sixth form will I be less likely to receive any financial aid and scholarship?