Enjoy celebrating Mexican-style; but, please don't call it "Mexican Independence Day" which it is not. Cinco de Mayo is the celebration of the battle of Puebla where an outnumbered Mexican army defeated the French forces on May 5, 1862. It's actually a bigger deal in the U.S. than it is anywhere but in Puebla, Mexico, perhaps.
It doesn't make the chips, guacamole and margaritas any less fun though. Have a good one!