Is it strange to use olives in Mexican/Tex-Mex food?!

Olives are not common in most Mexican meals, certainly not tacos or burritos. I don't know enough about Tex-Mex to say. The only Mexican dish, which is actually Spanish, that I know of with olives is pescado a la vizcaina. If you want to use olives in your Mexican recipes go right ahead. I love olives.
edit: I would point out to First L that the Spanish government forbade the planting of olive groves and vineyards in New Spain as Mexico was called in the colonial period. That is possibly why olives are not used that much in Mexican cooking. People do eat olives here, but they are usually sncaks to go with alcoholic beverages or part of salads.

I live and eat in Mexico.

Olives were one of the first foods brought with them by the Spaniards when they colonized the Americas. Spanish monks planted olive groves in all their monasteries, and they soon became very popular among the indigenous people. So if you're trying to re-create a typical authentic pre-columbian taco or tamal, then do not add olives, but as far as authentic modern Mexican cuisine, by all means, add olives!

Oh no, its not weird olives are a nice touch to authentic Mexican dishes its most common in enchiladas and in most tortilla based recipes. So no its not weird if anything its going to taste great. let me know how it works out fro you. :)

I am Spanish and love to cook