I consider myself antifa in part because my great grandfather was murdered by the Nazis, and I consider it to be part of my social and civil responsibility to oppose fascism.
Antifa is not just anti-facism. If you go to any of their rallies or counter protests you'll find most are socio-anarchists or communists who don't see anything wrong with violence.
While many antifa are anarchists or anti-capitalists, the defining feature is opposing fascism. Don't succumb to a trivializing caricature of antifa as being primarily about wanton violence against property.
Edit: ¡No pasaran!