Lincoln invaded Virginia, thereby starting the war. Confederates didn't set foot in Union territory until the war had been going on for over two years.
I always thought the South started the Civil War when they fired on and captured Fort Sumter. The first battle of Bull Run was only like 30 miles from DC, Lincoln had to send troops to fight the rebs in northern Virginia instead of the streets of Washington, to defend the capitol. Bull Run was the first major ground conflict in that war, but that wasn't where the war started.
Sumpter began the shooting war. Declaring secession and proceeding with extra-Constitutional measures was an act of sedition such as no nation that could be defined as such could tolerate. It was not a gentleman's club where one paid dues until bored and quit. The nation was joined together voluntarily sate by state. The people in each state supported that or not, but the state bound itself to a perpetual accord. A state, like a man, honors word given or does not and, like a man, is judged and dealt with accordingly.
When one is in a society where voice is given through the ballot, one accepts the majority decision. Otherwise, if the society permits, one leaves. Otherwise, one rebels and pays the consequences. Complaining about that after the fact only reveals lack of capacity for thought and/or mature decision making.