Study Abroad? Please I need help!

I am a sophomore in high school, and I am crossing my fingers that I can study abroad to Oman or Turkey my junior year {I cannot decide which yet!} through the YES Program. The program will last about ten months. As many of you most likely know, there are many benefits of studying abroad so I won't bore you!

There is nothing that I can think of that excites me as much as the possibility of studying abroad. I am currently studying Arabic at school and I want to expand my ability to speak a third language. Not only do I want to be able to do this, but I want to expose myself to a part of the world that is completely different from my day-to-day life. I want to expose myself to the Middle East because I want to eradicate the false misconceptions that have been planted in mind ever since 9/11. I want to get out of my sheltered life and be uncomfortable. Going to a country such as Oman or Turkey will get me out of my comfort zone and will help me grow into a more independent, cultured young woman.

The concern:
My uncle came to visit about two months ago and he is a big part of my life. Whatever is going on in my life or is a concern, he is the person I call. So, naturally, the subject of me wanting to study abroad came up. Let me remind you that my uncle is not your average joe. He is an extremely cultured man, not to mention one of the smartest people I know. His opinion is always one with much thought behind it.
When he heard what I had to say about studying abroad, he disagreed with it. Immediately he asked me what I wanted to do when I grow up. I said, "Doctor, of course." He gave me an elaborate explanation as to how leaving for an entire year studying abroad in high school would, in turn, hinder my academic abilities and I will not be able to "catch up" with the material I will be thrown at when I come back for my senior year. He said that that one year that I will be missing would really set me back.

Is my uncle's opinion true? As college students or graduates, would you say that I would lose a large chunk of my "academic ability?" I am challenged daily in school because I go to a high school that is notorious for its college-preparatory curriculum; I have a 3.8 GPA and I am heavily active in doing volunteer work. I am not looking to study abroad as a way to "escape." If I were to go to Oman or Turkey, I would go to a private school, not some rural shack in the middle of the desert.
Does a college truly validate an applicant's experience traveling abroad? In general, would traveling abroad to Oman or Turkey be an advantage besides for the obvious reasons?