What advantages did the South have upon entering US Civil War?

Some of the best officers in the US Army had resigned to join the Confederates.

An enthusiastic cavalry tradition - most young men owned at least one horse, and were used to the riding and shooting way of life.

At this point, they looked like gaining recognition and military aid from Britain and France.

They were not planning to invade the North at the beginning, so they had only to defend their home territory, unfamiliar to the enemy.

This also gave them a more powerful mission - defending the homeland.