Realistically, what are my chances of getting into Harvard or Brown?

I am currently a sophmore in high school. I have a GPA of approx. 93, and am taking, french, latin, & honors hist & english. I have played the fiddle (not in orchestra) for many years, and have done some volunteering at a local nonprofit music cafe. I am taking the SAT in Latin & world history this year & scored a 710 on the bio SAT last year. My PSAT results were: reading:75 math:51 writing:64 & my SAT scoes this year were: reading: 750 math: 630 writing 69- and essay: 9. I have participated in no clubs or sports. I am half native american (does that increase my chances?), and am probably in the top 5 or 10% of my class. I am not taking the most difficult math class, but I am taking the most difficult in everything else. Also, which of these would a college value more: 1) a paid summer job 2) a paid/ unpaid internship 3) taking summer classes at a college. Also, i am planning to study to be either a journalist or an englsh teacher. Thanks for answering!