If you want to know exactly how your hair will look like in a few years, then you should look at your parents, your uncles, aunts and your grandparents.
The state of their hair should give you a clue about how yours will look at a particular age. Many people lose their hair with age. Some go bald while some type of hair thins out on its own but does not disappear completely.
Genetics are hereditary and therefore influence the state of your hair. You can confirm this if you see a trend where your parents start losing hair at the same time your grandparents did.
Like any other condition or disease, genes make you predisposed to certain family traits such as hair loss. This is also because the size, texture and structure of your hair are influenced by your family line.
You cannot do anything about this cause for hair loss, except take care of your hair while it is still strong.