Mexico Mexican
If you were born in Mexico it represents the whole background of your experience.Also it can be an expression of what your feelings about Mexico are and how you would describe it to another person.
If you have lived in Mexico than it would be your overall feelings about being there, obviously altered by the details of the dream.
If you have never been to Mexico then it represent what your impressions of it are.
Useful Questions and Hints:
Did meaningful things happen to you in Mexico?
What would you say was the main things about being Mexican?
How has Mexico influenced you?
See Being the Person or Thing – foreigner – Serpent of Mexico