Now that you know how little it takes to get started, you might want to decide on a role. Ask yourself a couple of questions.
Which side should I take, North or South? Keep an open mind, many reenactors have costumes for both sides, and at certain periods in the original events, it was hard to tell sides. Many Confederate Officers in the early war had left the original Union to fight for their home states. They still wore the Blue Uniforms, as that was all they had.
Do I want to be Infantry, Cavalry, Artillery, Provost, Sharpshooter, Medical, or one of the many other roles available?Most reenactors start as Infantry soldiers, and younger boys find themselves indispensable as flag bearers, as many reenactments kill off several per battle. Ask around about the role you think would be interesting to you. Original battle units were vastly larger than most reenactments, so there is quite often room for an additional character.
First step should be to scout the event on Friday night while everyone is settling in after setting up camp. Walk through the camps and visit with the reenactors. Get to know who's who. As in all things, there are people to cling to and people to avoid. You will meet people from all walks of life, and with standards to match. People who quote scripture and people who tell dirty jokes. Sometimes,they are the same person... Keep an open mind while walking through the camps. Many military reenactors will spend Friday night around the campfire telling stories of reenactments past, with proud moments and horrible shames. These guys are getting into their roles in a way similar to how movie actors develop the characters they will portray. Listen well, and you could be drawn in and relive history as if you were there.