Lois is given to have been born in 1967, Clark's birthdate is Feb 28, 1966. We aren't given a birthdate for Luthor, but the actor was born in 1949.
In 1993, the start of season I, Clark was 27, Lois was 26, Luthor was probably 44.

Big Apricot Superman Movieverse
The World of Lois & Clark
Richard White to Lois Lane: Lois, Superman is afraid of you. What chance has Clark Kent got? - After the Storm