These days there’s a wide range of abilities and disabilities from age 20 to 100+. It’s no longer possible to predict what to expect by the decade.
Seniors are joining in the exercise craze lifting weights and running marathons. Folks are staying out in the work force longer, too. It’s not unusual to find an older adult who does physically demanding manual labor.
Most likely the answer you gave to the question helped the therapist get an idea of your daily activity level and functional abilities. Establishing a baseline of activity is important in order to know what goals to set and how to get there.