UGA is tough, but you already know that. If you're prepared for heavy cuts and willing to look hard at the houses who are giving you a chance, then I would also say to go ahead and go for it. You will never know if you don't try, and that's the only thing that is a certainty at UGA.
Here's my experience as an upperclassman pledge--I probably would've ended up in a totally different place if I had gone through rush as a freshman. I was from a really, really small rural town and I knew only one person in a sorority at my school. I regretted not going through rush everyday of my freshman year, but I had made a lot of friends in sororities and got involved in a lot of things, so by the time I went through rush, I had very good friends in a few different houses who were pulling for me. I got cut pretty heavily after the first day, but I had a full schedule for pref and I got my first choice. I really didn't have any close friends in my pledge class, most of my friends were my age and older, so if feeling awkward about being with girls a year younger is one of the only things holding you back, it may not be an issue. In any case, no matter what sorority you join, you usually find about 5 or 6 girls with whom you really click, and those are your friends.
Good luck if you decide to go for it. I'll be thinking about you along with all of my daughter's friends who are going through rush at UGA this fall and hoping for happy results for everybody. I know of one girl from our HS who did not have a good recruitment last year who is trying again, so you won't be the only one going through that experience.
(and although my older daughter is constantly correcting me...I'm old, so I'm going to say rush, pledge and house instead of recruitment, PNM and chapter

)