joining when older?

It's pretty weird, especially for sororities. If you're joining a sorority, most of the girls in your pledge class will be 17-18 and in their first year of university. The new member period is when you learn about the sorority before officially pledging.

Even the older girls will be maximum 22, and will have been in their sorority for a long time and will already have made their close friends.

Fraternities are a bit different since some guys do join in their fourth/fifth years, but again you would still be by far the oldest (not sure if you're a girl or a guy).

There are other organizations on campus that would probably be a better fit if you're in the 24+ range

People in the US do it all the time. They go and do professional things like military or flight attendant and then go back to school and join a Greek org. I 'm not sure it is done here as much. I can think of ta few people that were in their mid - 20s. It is what it is. If you want to do it, go for it.

theres honestly no harm in trying if an org wants you they'll take you and the only way to know is to try!!

Yolo
Why not, rush, experience recruitment.
If a sorority or fraternity accepts you that is great, if not then at least you experienced it.
I know some older greeks in the system, and they fit in just fine.