Five.
Twelve, though Truman was only president for four months of it.
These 13:
Franklin Delano Roosevelt, 1933-1945
Harry S. Truman, 1945-1953
Dwight David Eisenhower 1953-1961
John Fitzgerald Kennedy, 1961-1963
Lyndon Baines Johnson, 1963-1969
Richard Milhous Nixon, 1969-1974
Gerald Rudolph Ford, 1974-1977
James Earl Carter, Jr., 1977-1981
Ronald Wilson Reagan, 1981-1989
George Herbert Walker Bush, 1989-1993
William Jefferson Clinton, 1993-2001
George Walker Bush, 2001-2009
Barack Hussein Obama, 2009-
12 for me, although I don’t really remember much about the Truman years. But I definitely remember campaign buttons saying “I Like Ike.” And like Panache45, I was a freshman in college when JFK was assassinated. Back then, there was only one TV in the dorm and not that many radios in dorm rooms. I remember many of us clustered around a single radio (on a windowsill to improve reception).
I was born a few months after JFK was assassinated so I’m only up to nine. I don’t remember Johnson as President but I remember standing in line to view his casket here in Austin. I can remember talking trash about Nixon and being upset that the hearings preempted my afterschool TV shows. I first voted in the Reagan election.
Thirteen. But don’t remember Roosevelt at all.
The first President I do remember was Truman. I thought it was so neat that he sounded just like Gene Autry. And Eisenhower sounded surprisingly like Clark Gable.
Nine since birth. Although I was conceived during the Kennedy Administration, and was thus technically alive, I didn’t count that. 
ETA: The first one I remember is Nixon.
- And I listed them before looking at the cheat sheet.
I like this thread - it makes me feel young *and *smart!
Seven, though I only remember 5 of them. Actually, the first memory I have of being aware there was such a thing as a President was the Reagan shooting, when I was confused about why they were pre-empting my cartoons.
Nine. I have vague memories of Carter’s election.
Same here.
Truman … Obama = 12. Thanks for the list, btw.
8
Starting with Richard Nixon who was inaugurated 5 days before I was born.
Me too. One of my earliest memories is the shock the day Roosevelt died (I was 8).
Nitpick: I thought it was Harry S Truman.
That’s how I’m remembering it, too. The S stood for nothing but a middle initial. I was 3 when FDR died. I only have bits and pieces of real memories of Truman, but have picked up a lot from newsreels and documentaries since that time.
- I was born during Eisenhower’s first term.
The first I remember was JFK. Both for the Space Race and his assassination. We were called out of class to gather around the flagpole to say the pledge of alliegence, and all the teachers were crying. I didn’t understand what had happened until I got home and my parents explained it.
8 so far; Nixon was the first.
Eight but the first President I have memories of is Carter.
I was born during Reagan’s presidency, so 5 for me.
Seven, though I don’t remember Gerald Ford at all.
My great-grandmother (born 1900, lived to be 105) would have seen nineteen presidents in her lifetime, as would my great-grandfather (1888-1984) if you count Cleveland twice.
Someone who was born early in 1837 and lived to be just over 96 would have lived under 26 presidents, well over half the American presidents there have ever been. I always find that kind of mind-blowing.