We in Spain use "where are u from?" as "¿De qué país eres?" cause we refer to the country u are from.
¿De dónde eres? is a bit different cause it can also be used for cities, place or even, for example, at schools, refering to which school you came from.
In spanish "te" is use in sentences to refer to "you" as the object of the sentence, for example:
ComeTE toda la comida del plato. It is that u have to eat it, TE refers to who has to eat them, so, as in this case, you.
Remember than "Mi" (posesive, my or mine) is not the same as "Mí" (myself).
Hope this will help, greetings from Spain!