You think it’s 14% because there aren’t that many that fit the criteria?
I would guess there actually are millions of kids that fit; the low acceprance probably reflects the fact that acceptance is the equivalent of getting $500,000 (in education funding) for free.
Sure, not every kid would be able to handle a tough curriculum, but I believe the school has honors/AP type classes as well as dual enrollment ones. And the OP sounds to me like s/he meets the stated criteria. I wouldn’t lightly dismiss guaranteed free college (let alone boarding school).