According to a CBS News / YouGov poll, 77% of American voters think there should be "maximum age limits for elected officials."
But there already are "maximum age limits for elected officials."
They're called "elections."
Think someone's too old to hold office? Don't vote for him or her. "Problem" solved.
The framers of the US Constitution obviously didn't think age was a problem -- they set the minimum age to hold the presidency at only one year less than the average lifespan circa 1790.