Couple of things. The kid is a very good player, did the hold back year help her ,I would bet it did . Did it help her even when playing" up" at 2019 as in " that kid is really good considering she is a year (grade) younger" probably. The fact is the college coaches do not care and do not ask the kids how old they really are so the parents used that to their advantage so good for them. Is some of the animosity toward the kid because people are just plain jealous of her ability, absolutely, is some of it because parents are embarrassed that they did not take advantage of "the hold back" to help promote their kid ( takes some courage to do it especially because of the social stigma that your kid was left back presumably because they were not academically gifted enough ), probably.