How to know if you're a Marxist? This is what a Marxist says:
Here are the basic principles of Marxism:
• Opposition to an economic system based on inequality and on the alienation and exploitation of the majority (by means of the system of wage labor), a system whose purpose is to obtain profits for some people rather than satisfying the needs of all. This describes capitalism, but one can obviously imagine other systems that would present similar essential characteristics, to which Marxists would be equally opposed.
For the transformation of society, Marxism considers that a revolutionary process that will lead to a society based on cooperation and the free distribution of goods and provision of services is necessary.
• “The emancipation of the workers must be the task of the workers themselves.” This is principle is inherent to real Marxism, which implies democracy and self-emancipation; it also means that democracy is the indispensable foundation for a new society (called socialism or communism). This society, liberated from the diverse forms of domination, will have to be freely constructed by its members.
• Internationalism, which is simultaneously the recognition of the common interests of the workers of the entire world and of the need to struggle on a world scale, and of the goal of abolishing nations in the transition to a human world community.
• The knowledge and analysis of History (the materialist conception of history).
• The recognition of the existence of social classes that divide men and women into distinct segments of the population; the recognition of the profound inequalities and injustices that separate these classes; and the recognition that as long as society is divided into classes, there will be conflicts between these classes (the class struggle).
As a result, while they participate in the day-to-day class struggle of the workers, Marxists work on behalf of a reorganization of society that will put an end to this class division.
• The free exercise of the critical spirit. “Doubt everything”, Marx said; for the goal is to perceive reality as it is, in order to understand it better and thus to transform it.
If this is what drives you, you're probably a Marxist. Notice that some of these apply to other groups like many conservatives (class warfare) or many liberals (doubt everything). But if you follow all of them, you're probably a Marxist.