Do American counselors in Nepal really allot visas for "high school student exchange" programs? May be if it were organized under some Nationally known/ backed up projects or some ventures? I myself have seen young French high school kids coming to America as exchange students and staying for a couple of years and leave, but for Nepal I have never heard anything like that.
Why France and not Nepal, you may ask now. The reasons are obvious. They share very good relationship since history (America always treats France as its sister, some history trivia there) and the most important it is a developed, rich European country with no bad record of its people staying illegally in America. I don't deny some outliers though.
Otherwise, if you want to apply for student exchange program, then most probably one has to start the first step of visa application by getting some sort of invite (as in I-20) from the school itself, right? But the possibility of getting the visa approved, I have my doubts, because 14 years is vey young age for any kid from Nepal to have any known 'ties' to the country. The likelihood is like the maximum that the kid can potentially immigrate and stay back, and the counselors know immigration policy is lenient on minors.
People correct me if I am wrong.