This is a question for a doctor experienced in sports medicine. IF you've been using good shoes, IF you're a gifted runner with a smooth gait, IF you are genetically well set up for running, IF you've had no bad falls or injuries, and IF your joints stay well-lubricated - you might run for years. But you could also start having problems tomorrow.
Running is obviously important to you - but could you divide your time between running and perhaps swimming NOW and slowly transition a bias towards running to a bias towards swimming over time?
Remember that you are entering "middle age" when testosterone values decline, as does GH production. Your joints and tendons will not be as healthy in the future as they are now.