While I feel for the girl (she is not a favourite but I have to admire her rare skill) someone - quite a few someones - was going to feel and be disadvantaged by the age going up, no matter how and when and whatever they did, it would hit someone. The sheer coincidence of the said disadvantaged being the prodigy of her generation is mind-boggling but if they don't want sixteen-year-olds in the seniors ranks any more, they don't. Having made the decision, they could hardly backtrack for the benefit of one person.
Maybe it will turn out to be a mistake, maybe we will all wonder why it wasn't done earlier, We won't know for some years at the earliest.