What exactly is genes or dna and if there is any method to decode one's dna & will the preson doing it be able to know up to what age one can live?

Genes are: Made of dna and are found in chromosomes. They code for all the proeins which are responsible for your essential makeup. Life span prediction in a healthy person is not able to be predicted as of yet. Lifestyle plays a big role in life span, good luck.

Asking a lot : Dna is the chemical code building blocks that make living things what they are. We are able to read the code but it is not easy and costs a lot. The big problem is for the most part we don't know what it means. Wait a hundred years and we may be able to do just what you asked.

No prediction: You've assumed that every bit of your health is encoded in your dna and that one can predict your longevity... That is not the case. So many factors go into one's lifespan, including habits, diet, exercise, and of course, genetics.

Too extensive a ?: Briefly: chromosomes are made up of strands of dna along which reside Amino Acids that code for proteins that are built inside the cell in the golgi apparatus. These then become the building blocks upon which all life is based.Dna has been encoded for dr. Watson, the first person to ever have it done in his honor because he discovered it along with dr crick (deceased). Can't yet predict longevity.