A few suggestions
Andrea, I'm in CA, and unfamiliar with your specific laws, but am not surprised to learn from the other person here the specific statute relating to stopped emergency vehicles. I usually drive too slow anyway, and automatically move over if I can, either around stopped vehicles, or towards the shoulder to let tailgaters pass. As far as going to court, which I've had to do several times over the years, including right now, some basic advice I can offer is that, unless you take the time to become VERY familiar with how to fight a charge in court, you will almost certainly lose. Sorry to have to say that, but I think most every other veteran here will agree. This is not to completely discourage you, but to be realistic, since the procedures are set in stone, and neophytes can rarely ever come up to speed in time to have a fighting chance. Even so, there are many resources out there to help you better prepare yourself if you choose to, including a live attorney, which the court should appoint for you if you lack the means (even in GA!). Frankly, tho', there is little point fighting a ticket if you are basically guilty, unless there was some major screw-up on the officer's part, or serious reason for you having to commit the error. Check out lawcollective.org for excellent help on dealing with police and the court.
The good news, on the other hand, is that judges generally DO respect people who appear in court, and are respectful, even if they're pleading guilty. Given what you described, there appears to be no way out of your "guilt," but you can plead "mitigating circumstances," which judges will usually always take into account, as long as they aren't far-fetched. This means that you admit making a mistake, but not through intention, or carelessness, but ignorance, and that your driving was safe and lawful in every other respect. You can also admit that you are willing to pay the fine for your unintentional error, but request that it be "mitigated" due to your financial circumstances, as well. I have had judges respond favorably to me, and have seen it with others, too, a number of times, with fines being reduced or dropped altogether -- but don't assume that WILL happen. Here in CA, the court will usually allow you to make payments on the fine instead of demanding it all at once (with a set-up fee included, of course!). Not sure if that is the case in GA, but I imagine it probably is. I wish I had more sunshine to offer, but I'm afraid that's about it. Keep in mind cops and judges always consider the "deterrence factor" in assessing penalties. If it's steep enough to hurt, you will definitely NOT want to make the same mistake again, and you'll also undoubtedly tell many of your associates about it, and deter them, as well... C'est la guerre...
Cheers, MK