Actually, Blacks did serve in the Confederate Armed Forces from the first day of the War. Just not in the Army. Blacks could be enlisted in the Confederate Navy up 10% of the ships crew. The Captain could request a waiver from the Confederate Navy Department and recruit more than 10% if he needed to. Black sailors made up about 12% of the Confederate Navy. Blacks also made up about 16% of the U.S. Navy during the Civil War.
I’ve read an article several months ago about Blacks serving as soldiers with Nathan Bedford Forest. He promised them freedom in exchange for their service, and all but one stayed with him till he disbanded. True to his word, he gave them their freedom papers before the agreed upon service had been completed, because he wanted to make sure that if he died in battle, their freedom would still be protected through those papers.