If Bernie Sanders wins the 2020 United States President election, he would be the oldest President in U.S. history. He would swear in at the age of 77. If Vice-President Joe Biden decides to run and wins the election, he would be the oldest at age 76. At present, Trump is the oldest American President at the ripe young age of 72. Ronald Reagan has held the record for the oldest President and John F. Kennedy wins for the youngest.
Some are a bit concerned about Sanders' age and have been very vocal about it. There is always the possibility that a Vice-President will have to step in should Sanders succumb to old age or anything else that would cause his death. Still, that concern doesn't seem to be enough to drain his fan pool. People love him and ultimately, that's what matters when it comes to sticking by a candidate all the way to the polls.