I would say that the first Confederate state is South Carolina because it was the first state to leave the Union(secede).
Do you mean when it was first admitted to the USA? Or do you mean when it became the first Confederate state?
South Carolina was the first of the Confederate States to secede from the United States.
Briefly, Montgomery Alabama, then Richmond, Virginia.
Tennessee
The US state of Alabama has Montgomery as its capital. Alabama became the 22nd US state in 1819. As an aside, Montgomery was the first capital city of the Confederate States of America in 1861.
The confederate states that bordered the union states varied by time, as some states changed sides or became neutral. Virginia was the only one that stayed the same, bordering Ohio, Pennsylvania and Maryland.
Florida became the 27th state of the United States on 3 March 1845. Also, Florida was the 3rd state to secede from the United States on 10 January 1861, and it became one of the six original states of the Confederate States of America on 8 February 1861. After the end of the U.S. Civil War, Florida was the 3rd Confederate state readmitted to the United States on 25 June 1868.
On December 10, 1817, Mississippi was the 20th state admitted to the Union. On January 9, 1861, Mississippi became the second state to declare its secession from the Union, and it was one of the founding members of the Confederate States of America.
The land area known as Arizona today was once a part of the Territory of New Mexico, became a part of the Confederate States of America as the Confederate Territory of Arizona and later became Arizona Territory with a new dividing border with New Mexico. Arizona became a US State on 14 February 1912.
Confederate, but thousands of citizens remained loyal to the United States.
Texas became the 28th state in 1845. It then suceeded and became a confederate state March 23, 1861. It became an American state again after the civil war was over and the confederate army surrenderd to the union.
December 7, 1787 was when Delaware became the first state to ratify the Constitution of the United States, thereby becoming known as the first state of the United States.