First of all, you've got three more years to figure this out.
Joining the Peace Corps is an admirable goal but give yourself a chance to experience college first and see where that leads you.
There are a number of Peace Corps-like programs right here in the United States. Some, like Teach for America, have a two year commitment and provide funds for graduate school if you fulfill the two years. Others, like some of the VISTA programs, are only for one year and offer less money for grad school.
These programs take place in major urban centers and in rural parts of the US. They can be every bit as rewarding as the Peace Corps and yet you'll still be on the same continent as your family.
Many programs (Teach for America and VISTA among them) are under the auspices of Americorps. Spend some time on the
AmeriCorps website and you'll see a variety of options.