If you were born here and lived here most of your life, or all your life, you have the choice of calling yourself an American or a Mexican American or a Salvadorian American or even just a Hispanic or a Latina.
You can be proud of where your parents came from, the culture you were brought up with, and call yourself a Something-American, or you can simply be an American. Your choice.
My grandparents were kicked out of Ukraine about 100 years ago, for being Jewish. In Ukraine Jews lived in their own villages or neighborhoods, they wore different clothes, ate different foods, spoke a different language, and they were treated badly sometimes. So when they came to the US they wanted to be just American Americans, to speak English at home and raise their kids to be mainstream American. But I consider Judaism more an ethnic heritage than a belief system.
So anyway, you can be what you want. It's up to you.