I grew up with the original Superman, the 'canonical' one. Superman appeared in comic book form in 1939, reprinted several times in the 1950s, and I had a reprint copy at one point. The thing is, Superman has been rebooted at least two or three times, and each time the story was changed to make it more current and modern.
Now, ORIGINALLY, the "S" on Superman's costume was not an S at all, it was the family crest of Jor El, Superman's dad. People saw it and wondered what the S stood for, so someone suggested 'Superman'.
But in the original story it was never suggested that Superman was not a man, not 'human'. His planet, Krypton, was 70 times the size of earth, meaning it had much stronger gravity, so humans had evolved on his planet to be very strong--just as an ant can carry 70 times his own weight. The origin story showed that if a man was proportionately as strong as an ant he could lift a railroad car. (BTW because of this strength, the original Superman could 'leap tall buildings at a single bound', but couldn't fly!
But Superman was human enough to go through 12 years of school, then college, without anyone suspecting him. I always thought it was a little strange that he just put on a pair of glasses and nobody recognized him, but remember, this is a COMIC BOOK!
The problem with the 'canonical' Superman is that they began changing the canon immediately. In the comics, whenever Superman came up against some problem that couldn't be solved with super strength, he suddenly developed a new super power. Xray vision, heat vision, super hearing, the ability to fly, even to fly through space at hypersonic speeds. The ability to move planets into each other's paths, and even to reverse the rotation of the earth!
In the Superman radio series, which began only a year after he first appeared in the comics, Superman grows up on the trip from Krypton to Earth and emerges from the space capsule as a full-grown man dressed in a SUIT! This allowed them to dispense with his childhood in Smallville and get to the fun stuff right away.