Former President Jimmy Carter in September 2018.Scott Cunningham/Getty ImagesFormer President Jimmy Carter will turn 100 on October 1.Grandson Jason Carter told The Atlanta Journal-Constitution that Jimmy Carter has been "more alert."Jason Carter, an ex-lawmaker, also said his grandfather wants to vote for Kamala Harris.Former President Jimmy Carter's 100th birthday is on October 1, and the ex-commander-in-chief is excited to reach the huge milestone.The 39th president is also eager about potentially reaching his birthday because it would likely mean a chance to vote for Vice President Kamala Harris in the presidential election, according to The Atlanta Journal-Constitution.Former Georgia state Sen.