I like your comment ' I am under 60, so am still young.' With your permission, I'd like to use that so when I next get an opportunity I will say to someone something like, "I'm 75, so I'm still young." Sounds good!
When I'm out running people that I stop and speak to have a habit of asking me how old I am when I tell them they usually say something like "Oooh, you don't look it." I'm never sure if they mean it, are just being polite or are extracting the urine?