Athens, Georgia is the college town for UGA.
There will be religiousness, but not enough to keep you from safely and happily being yourself.
It's warm. It's a cow town so there's open-ish land, but with a college, there are plenty of younger folks--who tend to be more open-minded in a lot of ways.
With the starving college student factor, it shouldn't be too hard to find roomies, which makes living fairly inexpensive.
It all depends on how warm is "warm" to you. The daffodils start blooming in February. The Canadians' comments about Atlanta (when I used to work with a lot who travelled) was, "Wow! Ten months of golf! The other two months it's too hot."
Air conditioning here is necessity, not luxury.
Still, I used to live in Orange County (Warwick), and we moved to South Carolina one January. It felt like spring had come, immediately, but I acclimated fast. Of course, I was seven, but you're young enough it would probably go okay for you.
I had a coworker once from Ohio who didn't like the cold. So he started with Atlanta and figured he'd move farther and farther south, if necessary, until he found a good job in the warm.
I don't know what the job market is like in Athens.
I do know that Atlanta is pleasant. I've lived here for twenty-one years and love it. It's not like NYC at all---it's very green, lots of trees everywhere, and plenty of parks with greenspace.
I've never personally felt jammed together with loads of people here, but tastes vary.
Cost of living is higher than average, but reasonable if you live on the bus and train lines because you don't have to own a car---it just takes you twice as long to get to and from work that way. Most people that get to work on MARTA read or work or listen to music on headphones on their commute, turning it into a sort of downtime.
The other good thing about Metro Atlanta (I love this town) is that there are a bazillion different colleges and junior colleges to choose from so you definitely can get into one. Except, it's very hard to get in-state residency now before you're 25.
OTOH, if you do individual study well, you can study for and take CLEP exams during your pre-25 years and then apply to a school that will honor those credits. There are about 36 CLEP courses. Even if your college ends up not taking all of them, you will be prepared to take the class and ace it when you can. There are also a bunch of private colleges where tuition is generally higher than in state public, but will likely be lower than out of state public, and you can still qualify for financial aid since your parents won't be supporting you at all.
I'd suggest you at least visit metro atlanta and tour around it on MARTA out beyond the perimeter (I-285) before you decide against it if Georgia is the climate you want. There is so much opportunity here, including large counter-culture communities where extensive piercings and tattoos won't be a minus. However, in the larger work community, they would be an issue and, depending on the kind of job you want, you might have to figure out a way to tone down the "look" for work.
One of the better things is you can get here on greyhound, take MARTA out to the burbs to check into a relatively less expensive hotel, and then take MARTA back in to ride all over the line and tour the city and figure out if it's for you.
Avoid the southwest quarter of the city, as it contains most of the high crime areas and it's easy to accidentally wander into someplace dangerous for you if you don't know the city yet.
Spring is a great time of year in Atlanta, really pretty. It would be a good time to ride the dog and take a road trip.
Julie