The First Super-Girl

Before Supergirl came to Earth, whether as Superman's Kryptonian cousin (like Kara Zor-El/Linda Lee Supergirl in Action Comics #252 in May, 1959) or via another dimension (like the Matrix Supergirl in Superman #16 in April, 1988, though she didn't make a cover until Superman #21)...

...there was another Super-Girl!

The First Super-Girl

In Superman #123 (August, 1958 by Otto Binder and Dick Sprang), Superman met "The Girl of Steel".  Jimmy Olsen found a mystic totem that allowed him three wishes, and his first wish was to get a perfect mate for Superman...a Super-Girl! 

(Wow, Jimmy really is Superman's best pal!). 

She didn't last, and Jimmy's other two wishes for Superman didn't turn out so well either....with crooks taking the totem and wishing away Superman's powers, and Superman getting a chance to meet (though Jimmy spelled it "mate") his parents (so Superman help Jor-El and Lara become a couple!).

Odder still, when this story was reprinted in Superman Annual #6 (Winter 1962-1963) and in Superman #217 (June-July, 1969)...they only used the first 10 pages of the story (leaving off the second two wishes), and Super-Girl was colored to look a little more like Lana Lang...(which, oddly, is whom the Matrix Supergirl post-Crisis on Infinite Earths was based on as well!).  Great Caesar's Ghost!