I am going to disagree with lot of folks here.
My three daughters took Multi variable calculus while in high school. Obviously you are more gifted in math, but I think high school is a great time where you can explore and figure out what do you want to pursue. I would advise in summer experiment in other subjects. My daughters pushed themselves deeper in subjects they developed interests such as history, English, foreign language, economics etc. You have a gift and therefore have a luxury to experiment with different interests.
When you will work in real life you have to relate to people. Excel in intra-personal skills, improve writing (being an immigrant this was our priority). I suck at it but still try to express my views in my broken language. Go and have fun with life as taking calculated risks will pay off.