Nobody whether they have the longevity gene or not can predict how long their life is going to be. In some areas people are growing older and are healthier but this is no guarantee that all of us will reach a ripe old age.

Rather than worry about having a retirement plan, though it's maybe an option for you to look into, maybe you could look into a plan for living the best life in the time you do have allocated to you in the here and now.