Hello! I’m applying to Exeter, Andover, Choate, and Loomis Chaffee, respectively in that order for junior year. I am currently 14 years old, but I have missed the sophomore apply date.
Classes I Have Taken (with letter grades) :
Freshman Year: (First Semester)
Spanish 2.5 - A
Honors Biology - B
Honors English Language Arts - A
Honors Algebra 2 - A
AP Human Geography - A
Emerging Technologies - A
Sophomore Year:
Spanish 3.5
Sophomore Chemistry
Honors English Language Arts 10
Honors Pre-Calculus
AP European History
Honors Accounting
Extracurricular:
Tennis - Made top JV freshman year, my school was state champions.
I coach tennis to elementary students, and I have won EKL (tennis tournament) in my first year of high school.
Ballet - 8 years
Traditional Cultural Dance
Treasurer for my non-profit charity organization, Youth Hope Fund.
Piano - 8 years
I have gone to state auditions for several years.
Science Olympiad - Team placed third in my state.
Math - I won first place in the American Math Competition.
GPA: Unweighted was a 3.8 first semester.
Weighted was a 4.8.
PSAT:
Score: 1310 out of 1440
99 percentile.
Junior year is next to impossible to be admitted into. I’d say you should apply as a repeat sophomore. Your stats look great–a lot more impressive than mine, anyways–and if you write great essays and are comfortable in interviews, I’d say you’re in at almost all the schools you’re applying to. Make sure to contact coaches, if you’re an athlete. Good luck.
I know one person who was successfully able to transfer to Andover their junior year, but they had straight A’s in all their classes (which were all honor classes). Plus they were president of their sophomore year and homecoming queen freshman year (not that the second one probably helped). They were the president of four clubs and treasurer of a fifth one. They were in IB and had tons of volunteer hours. She worked two jobs and was on varsity volleyball and swim for both freshman and sophomore year. That wasn’t even all! Your resume is highly impressive, but I have to agree with dankfinesse that it’d be hard to get in. It also may be hard to get in by repeating sophomore year which would put you a year back. 
I agree about repeating. You are on the younger side anyway. SwimKid will turn 16 his freshman year as a repeat 9.