At 55 years of age can my teeth still be whiter? I was a smoker 24 years ago. (Photos)

If you have external discoloration (i.e. Staining from such things as tea and coffee), then professional tooth cleaning will help you. Bleach will not work well with external discoloration.
If you have internal yellowing, then you need to whiten your teeth using a whitening gel that is held onto the teeth.