Is it the woman's age that makes her a cougar/puma or is it the number of years between her and her man?

I'm 28 soon to be 29 (just over a month and a half away) and I'm dating a guy who turned 24 two months ago. My friends keep teasing me that I'm a cougar/puma cause of the four and a half year age gap but I still have over a year left before I'm 30. What do you guys think?