I think you're right. The problem is remembering how old they were when you last saw them. Usually (with five families on the go at the same time) the best I can manage is "in their 50s" or "in their 60s". I'm away at work for around eleven hours a day and it's difficult to remember. I suppose I could note down the ages of the older folks in the evening and morning to arrive at a more accurate figure, but that's a little like hard work.