Interesting question - my daughter will be applying for jr year as well. She is also on the young end of the class (august bday) and has no interest/appetite for repeating the grade. To her perspective - if she has a fabulous academic sophomore year - she be even less inclined to consider that option (less as in less than 0%!). To her, repeating a year after excellent academic performance simply due to her birthdate or year of entry doesnt make sense and she’d rather finish HS at her private school. In the end - even by repeating a year in BS - she could end up in exactly the same college as she would from her current school