One thing I have noticed with my cats: they did not seem to care for catnip until they were 'mature'..........meaning about 3 years old or so. My 1 yr. old (Wylie) has no interest in it now, and looks at my other kitty (Kedi) like 'what is WRONG with you?' when he is into it.

And Kedi himself did not like it until he was 3-4 or so. Now however, he is nuts for it- he has actually EATEN it before.