It could be age related cognitive decline, real or imagined, but it could also be prioritizing any of the following over learning largely irrelevant mathematics

It could be age related cognitive decline, real or imagined, but it could also be prioritizing any of the following over learning largely irrelevant mathematics: children and family, exercise, bills/finances/health care, social obligations, politics. Plus, it's much more likely for a 22 year old to be able to go to college / grad school and be required to learn math.