Or rather than reconsidering, think about what an 8th grade year, particularly at JBS, could provide you. For example, a chance to become familiar with the U.S system and to establish your academic credibility.
And placement counseling to position you for your best fit. Which might be Exeter but might be something you have not even considered.
It’s quite common forf international students to use JBS for this kind of assimilation, for lack of a better word.