Over my many years in the field of fitness, I've had countless conversations with individuals about exercise and improving their health. Quite often, I'll hear many diverse "reasons" why they aren't doing anything physical, but my favorite response by far is "wait till your my age - you'll see how hard it is".
I find this comment humorous on many levels. First, and foremost, because anyone at any age can find and use a safe, efficient and effective way to exercise. Second - and this is usually the fun part for me - I get to tell them that I'm actually older than they are. At that point they are just praying that their cell phone rings or someone calls their name so they can get out of this now embarrassing situation. This is not to say I look young, not at all, but staying in good physical condition does add a youthful appearance and attitude.
Of course, age is a consideration based on what someone is capable of doing - this means young and old - but regardless of age, everyone should perform some type of exercise.
Remember, "Age is a factor, not an excuse." - Fred Fornicola