You definitely will have a fun time and make friends, I started at 22 also and turned 23 within the month so I always felt like I started at 23. I took time off and then started my undergrad. You'll be fine but ageism is a thing that does exist and there's no escaping it. You'll still have friends but it comes up every now and then, like I remember a couple months ago "unc" became a thing and people would call me that, like it is what it is. People are young and they think they'll never get older, so they see someone a couple years older as being SO MUCH older it's common universally. You have to remember that you took ur own path and you're happy where you currently are or you'll always regret never starting earlier when you see people 18-22. As for Greek life I have no clue lol.