There are plenty of references to the Lexington shot being heard round the world, as especially it preceded Concord, and it remained uncertain which side fired first.
Respectfully disagree.
The Americans didn't put up a fight against the British at Lexington. No stand was made. It was a rout and Lexington was not unique in this way. Months earlier, the British marched to Salem and burned gunpowder and weapons the colonials had stored there. The mission was the same for the Brits going to Lexington and Concord. Find and destroy any weapons cached by the colonials and round of any leaders they might find (Hancock in particular).
Only at Concord did the Americans stand and fight. This was the true start of the war and a turning point in history where Americans took the battle to the British. Concord is correctly identified as where the shot heard round the world was fired.