Who was the President of the USA when you came into existence?
LBJ
ETA wow, I’m already on my 9th President.
Carter. Reagan’s the first president I remember.
Startin’ to feel old, Dio? 
Reagans the first president I remember as well, but I was born under Ford.
JFK.
Don’t remember him though, for obvious reasons.
Don’t remember Johnson either.
Definitely know the rest.
Truman. Can’t say that I remember anything about him firsthand, but I do have a vague recollection of Eisenhower v Stevenson in 1952 (specifically, “The Man of the Hour is Eisenhower”).
I was born a year after Reagan was first inaugurated. I don’t really remember him, but have clear memories of the first Bush.
I was born under Reagan (well not under-under) and he is also the first president I remember. Also the first time I had any concept of what year it was (or what a year even meant) was in 1988, still under Reagan.
I was born while Ike was in office. I don’t remember JFK, but I do remember LBJ. Ike, JFK, LBJ, Nixon, Ford, Carter, Reagan, Bush, Clinton, Dubya, and Obama - not sure what to make of that list.
Reagan, although there were less than three months remaining in his second term. The first president I was really aware of is Clinton.
I was only six during the Ford/Carter election, but I remember it. We had a mock election at school to parallel the actual race,and I voted against Ford because I thought his bald head was scary.
I remember being absolutely terrified by the prospect of the Reagan presidency four years later, as my parents thought he was an agent of Satan.
Reagan. I was old enough by the end of his second term to at least vaguely be aware of him as President. I think the '92 election was the first I was actually able to follow.
Give 'em hell Harry. The first one I remember being cognizant of is Ike in his second term.
JFK…right before the end. Wow, I’m old. 
Reagan, by a couple of months apparently. I think the first president that I had any contemporary awareness of was G.H.W. Bush, though.
Having never thought about it before, I just looked up who was Prime Minister of Canada when I was born: Trudeau. I have no memories of him, either, but I do of Mulroney.
The first I remember is Eisenhower, but Truman was the President when I was born.
Born during LBJ’s administration.
My first presidential recollections were about some minor kerfuffle Nixon got into. Something about water? Probably not important now.
George Herbert Walker. The earliest president I actually remember was Bill Clinton.
Carter - and I had to look it up. I could have sworn that it was Reagen.
The first one I remember is Bush 1.
I was honestly surprised when I learned that I was alive during the Nixon administration. Being born in 1973, all I remember back then was my parents being some hybrid of hippies and rednecks. I would say it seems just like yesterday but I honestly don’t remember a goddammed thing about it. Carter was the first president I remember and Reagan was the first president we had that anyone I knew liked.