It seems to me that clubs have this "rule" that you play with your school age for a reason! It would also seem that if you make the exception for one then why not for all, regardless of who you are, who your parents are or how good you are! Doesn't look good for the club when you let one girl play the birthdate/ school year card whenever it benefits her most! If she plays with 2019 now then she should end with them as well.