I didn't mean to suggest that I would undo a skip for sports, but I think that if DD15 had not repeated 2nd grade, she would not be playing school sports.

Sports had nothing to do with the repeat - she was immature and had the chance to repeat in a different school (and be in the correct grade per the public school birthday cutoff). I also thought she was not the swiftest of kids in an academic sense. She was labeled gifted in 7th grade, FSIQ over 130, years after the repeat.

However, it did happen to work out well with the sports. Unfortunately, you might not know the "right answer" to the question until your kiddo is grown. Of course this happens with lots of decisions you make for your kid - some will turn out well, some not as well - but you just do your best.