Earth-616 is on what's called, a sliding time scale, which basically means that most of the characters existing today have only aged a few years since their inception in the 1960's. So it's difficult to say with any accuracy how old any character actually is. Without the sliding timescale, Peter Parker was about 15 in 1963, and would be 61 today! With that in mind, Sabretooth seems to be older than Wolverine, but in the latest X-Men Origins: Sabretooth comic, his childhood was seemingly depicted in the early 1900's, not the late 1800's, as Wolverine's seems in Origins.