Congratulations on your purchase!
Regarding air conditioning, it really depends on what kind of driving you intend to do with the car.
I'm about an hour and a half north of you, and while my 280 has air, I've never used it. Just like I never put the top on / down. But I drive the car mostly on the weekend, and when the weather is nice.
It can get pretty hot in the summer, and I limit my driving to early morning or late afternoon or evenings. During fall, winter and spring, you really don't need or want the air conditioning.
So, depending on your planned usage for the car, you might want to hold off and see if putting in air is really necessary.