Study Abroad Senior Year?? Good Idea or Bad?

I want to study abroad but it'll have to take place during my senior year of highschool. I know about studying abroad in college, but I would like something nice to put on my transcript. I also don't want to miss graduation & want to make sure to take the classes I NEED to take to graduate. I just think that studying abroad is worth so much more than going to prom and stuff. So, I was thinking about taking first semester of my senior year to go abroad? Would that be hard to do? I heard that it's better to do it during Junior Year, but I can't.