How old is too old for BS?

A recent thread got me thinking, what is the age cutoff for boarding school? From the light research I’ve done, I haven’t seen anything about an age requirement for eligibility, and posts in older threads mention that there are twenty-year-olds enrolled in prep school (as PG students, I imagine).

I think boarding schools intended for high school students should have high school aged students. In the US that’s generally kids from about 14- to 18-years-old. If students fail or they have other issues they may attend longer. I think our state cut off is 21, but other states might be different. I think that’s reasonable.

I haven’t known of a student at my kids school that was older than 19 at graduation. Pushing 20 but still 19.

It is important to note whether or not the boarding school offers a PG year. Regardless, it would be unusual for a 21 or 22 year old student to be attending boarding school.

I’ve noticed many international students are a year older than their classmates (and many classmates have been held back/repeated 9th grade). I can understand this as even with being fluent in English, a non native speaker will have a steep learning curve at an academically rigorous boarding school, especially if they don’t come from western Europe, as there’s a cultural adjustment as well. Those kids are 20/21 when they graduate. So are some athletes, PG or not. Can’t speak to other groups, they could have older students, I just know the athletic/international kids best.

Thank you everyone for your responses!
@cinnamon1212 were older students rendered ineligible for certain opportunities (participation in national and international contests etc.) due to their age? I also can’t help but wonder whether someone who has entered their twenties would feel challenged at high school, not accounting for social issues. (Acknowledging that it is dependent on the individual.) Did older students also have peers the same age as them, or were they few and far between?

Do you think colleges are going to take seriously an award won by a 21- or 22-year-old who won it competing against 16- and 17-year-olds? If you’re old enough to have graduated from college why go back to high school? If you can afford prep school there must be some colleges that are affordable for your family.

Closing thread since the user is banned.